Obdsm1303 Hev
Obdsm1303 Hev
Engine .......................................................................................................... 6
Transaxle...................................................................................................... 7
Battery .......................................................................................................... 7
Misfire Monitor................................................................................................... 22
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 1 OF 179
Low Data Rate System.............................................................................. 22
UEGO Heaters........................................................................................... 76
A hybrid electric vehicle is powered by a conventional engine with an electric motor added for enhanced fuel
economy and reduced emissions. The electric motor can also be used to boost power and enhance performance
(like an extra "charge"). This type of vehicle is well suited for the environmentally aware driver who wants better
fuel economy and fewer pollutants, but doesn't want the hassle of plug-ins.
A vehicle can be "more" of a hybrid than another. There are various levels of "hybridization," mild, full, and plug-in.
With all HEV variants, the engine turns off when it is not needed, reducing fuel waste, and instantly restarts when
the need for power is detected. In addition, all hybrids provide electric assist, in that the combustion engine gets a
boost of electric power from the battery pack. This provides additional acceleration performance when needed,
without additional use of fuel. The main difference between the HEV variants is in the relative sizing of the electric
powertrain to the combustion powertrain.
A mild hybrid has a relatively small electric motor to provide traction power and a small capacity battery. It is
designed to provide a start-stop function along with a small amount of acceleration power (used to assist the
combustion engine) and a small amount of regenerative braking (meaning vehicle energy that would otherwise
would be wasted, is collected during braking to recharge the battery).
A full hybrid provides the same functions as a mild hybrid, but to a larger degree. Since it uses a larger electric
motor and battery, it can provide greater amount of acceleration and regenerative braking power. In addition, a full
hybrid provides an electric launch, whereby the electric motor can accelerate the vehicle without the combustion
engine for small distances. The electric motor can be used to accelerate by itself (in pure electric mode) or in
combination with the internal combustion engine (for greater power).
Plug-In hybrids have all of the functions and capabilities of a full hybrid, however, they use a larger battery which
gives them greater electric-only driving range. In addition, plug-in hybrids have a charge port which can be used to
charge the battery externally from electric mains to allow them to have full electric range without having to run the
combustion engine.
Engine
Battery
Series Mode
Stopped
The engine will be off unless it needs to be on for reasons other than tractive power (Max A/C, vacuum,
catalyst temp, heat, purge, low SOC)
Launching
At low speed or low power demand, the launch mode will be electric, unless the engine needs to be on for
other reasons.
At moderate speed or high desired power, the engine will come on.
Cruising
At light load, the system may operate in parallel, positive split or negative split mode depending on the
battery charge.
At heavy load (due to high speeds, weight, towing or grade), the system will be limited to engine only
performance (no battery support).
Limited regenerative braking will be used.
Exiting highway
Provides an opportunity for regenerative braking.
Braking
At high speed, the engine torque is ramped down, the traction motor regenerates to a limit and the
foundation brakes are applied as necessary (at the traction motor or battery regen limits).
At moderate and low speed, the engine will be turned off.
Vehicle Interior
o Cluster - Upon a charger fault, the BCCM and BECM can request the P/T malfunction indicator on the
instrument cluster (amber wrench light). No specific message to point to the charge system which is
similar to other onboard requests for this telltale.
o 8” Centerstack Screen - A charging fault message will be displayed in 8” centerstack.
Vehicle Exterior
The vehicle will have a light ring around the charge port located on the driver’s fender. Upon a charge fault, all
segments of the light ring will flash rapidly for 20-30 minutes.
Lighted ring indicates fault and state of charge Ring illuminates in 4 segments representing
25% increments of battery state of charge
The convenience cord includes a CCID box with HMI display. A triangle with a (!) LED in the center indicates the
following fault conditions:
o CCID self test failure
o CCID microprocessor failure
o GFCI final fault
o Over current protection “final” fault
Red LED light illuminates indicating fault conditions. LED blinks unique codes depending on fault:
o Vehicle fault – 1x / 2 sec
o Contactor fault – 1x / 1 sec
o CCID fault – 2x / 1 sec
o Ground missing – 10x / 1 sec
o Failed internal self test – on steady
Standard feature allowing cellular communication between vehicle and cell phone/computer
New vehicle purchase includes pre-paid 5 year subscription (renewable)
Upon charge fault, automatic alerts will be sent to the owner’s cell phone and/or computer via text/email message.
The following reasons will trigger an alert:
o Charging Fault (during charging only)
o Scheduled Charge Not Occurring
o Accidental Unplug - if charger is unplugged and vehicle not driven within 15 minutes
Upon request by owner, MyFord Mobile App also sends vehicle reports containing other information that could
point to a charging fault:
o Charge status, including: generic fault (not known if in the car or out of the car), fault inside car, fault
outside car, charge in progress, charge scheduled, and charge complete
o Plug status
o Battery health – if BECM not requesting telltale, health is ok
deceleration Battery
torque Power
BPPS desired Management
BECM/
BSCM /
Regenerative Battery
Brakes
The Hybrid Electric Vehicle Control System uses four modules to control hybrid electric powertrain functions:
The Engine Control Module (ECM) monitors driver inputs and controls engine related functions.
The Hybrid Powertrain Control Module (HPCM) interprets driver inputs and controls energy
management and generator and motor functions.
The Battery Energy Control Module (BECM) controls the high voltage battery pack.
The Brake System Control Module (BSCM) monitors driver braking requests and controls the braking
functions.
All these modules use CAN communication for all diagnostic functions and normal-mode communications.
The ECM is a stand-alone OBD-II control module and meets all J1979 requirements. These include generic
DIDs, freeze frame storage, pending and confirmed DTC retrieval and clearing, Mode 06 test data, Mode 08 evap
system test, Mode 09 VIN, CALID and CVN, and Mode 0A Permanent DTCs. The OBD-II monitors for the engine
are similar to the monitors used by a conventional gasoline vehicle. The basic difference between a conventional
gasoline engine and the hybrid engine is that the engine often shuts down while in electric mode. This sometimes
requires active intervention by the diagnostic executive to ensure that all OBD-II monitor can complete.
The HPCM is a stand-alone OBD-II control module and meets all J1979 requirements. These include generic
DIDs, freeze frame storage, pending and confirmed DTC retrieval and clearing, and Mode 09 CALID and CVN,
and Mode 0A Permanent DTCs. Some of the OBD-II monitors for hybrid system are similar to the monitors used
by a conventional transmission; however, many of the monitors are unique to the hybrid generator and motor
sensors and controls. The HPCM is housed within the Inverter Control System (ISC) models, and is not
serviceable with the exception of reflashing memory.
The Brake System Control Module (BSCM) is not an OBD-II control module because there are no regenerative
braking faults that affect emissions.
The Catalyst Efficiency Monitor uses an oxygen sensor after the catalyst to infer the hydrocarbon efficiency based
on oxygen storage capacity of the ceria and precious metals in the washcoat. Under normal, closed-loop fuel
conditions, high efficiency catalysts have significant oxygen storage. This makes the switching frequency of the
rear HO2S very slow and reduces the amplitude. As catalyst efficiency deteriorates due to thermal and/or chemical
deterioration, its ability to store oxygen declines and the post-catalyst HO2S signal begins to switch more rapidly
with increasing amplitude. The predominant failure mode for high mileage catalysts is chemical deterioration
(phosphorus deposition on the front brick of the catalyst), not thermal deterioration.
The Integrated Air/Fuel Catalyst Monitor assesses the oxygen storage capacity of a catalyst after a fuel cut event.
The monitor integrates how much excess fuel is needed to drive the monitored catalyst to a rich condition starting
from an oxygen-saturated, lean condition. Therefore, the monitor is a measure of how much fuel is required to
force catalyst breakthrough from lean to rich. To accomplish this, the monitor runs during fuel reactivation following
a Decel Fuel Shut Off (DFSO) event. The monitor completes after a calibrated number of DFSO monitoring events
have occurred. The IAF catalyst monitor can be used with either a wide range O2 sensor (UEGO) or a
conventional switching sensor (HEGO).
The monitor runs during reactivation fueling following an injector cut. The diagram below shows examples of one
DFSO event with a threshold catalyst and with a Full Useful Life catalyst where:
Fuel (lbm)
0.012
1.5 0.01
0.008
1
0.006
0.004
0.5
0.002
0 0
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Tim e (sec)
In this example, CATMN_IAF_SUM is small because it doesn't take much fuel to break though a low oxygen
storage threshold catalyst.
2 LAM
Fuel (lbm)
CATMN_IAF_SUM 0.012
1.5 0.01
0.008
1
0.006
0.004
0.5
0.002
0 0
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Tim e (sec)
In this example, CATMN_IAF_SUM is much larger because it takes a substantial amount of fuel to break though a
high oxygen storage threshold catalyst.
There are two sets of entry conditions into the IAF catalyst monitor. The high level entry conditions determine that
the monitor would like to run following the next injector fuel cut event. The lower level entry conditions determine
that the fuel cut-off event was suitable for monitoring and the monitor will run as soon as the injectors come back
on.
o The base monitor entry conditions have been met (ECT, IAT, cat temp, fuel level, air mass)
o The catalyst/rear O2 has been rich at least once since the last monitor event.
Rear HO2S sensors can be located in various ways to monitor different kinds of exhaust systems. In-line engines
and many V-engines are monitored by individual bank. A rear HO2S sensor is used along with the front, fuel-
control HO2S sensor for each bank. Two sensors are used on an in-line engine; four sensors are used on a V-
engine. Some V-engines have exhaust banks that combine into a single underbody catalyst. These systems are
referred to as Y-pipe systems. They use only one rear HO2S sensor along with the two front, fuel-control HO2S
sensors. Y-pipe system use three sensors in all. For Y-pipe systems which utilize switching front O2 sensors, the
two front HO2S sensor signals are combined by the software to infer what the HO2S signal would have been in
front of the monitored catalyst. The inferred front HO2S signal and the actual single, rear HO2S signal is then used
to calculate the switch ratio.
Many vehicles monitor less than 100% of the catalyst volume – often the first catalyst brick of the catalyst system.
Partial volume monitoring is done on LEV-II vehicles in order to meet the 1.75 * emission-standard threshold for
NMHC and NOx. The rationale for this practice is that the catalysts nearest the engine deteriorate first, allowing the
catalyst monitor to be more sensitive and illuminate the MIL properly at lower emission standards.
Many applications that utilize partial-volume monitoring place the rear HO2S sensor after the first light-off catalyst
can or, after the second catalyst can in a three-can per bank system. (A few applications placed the HO2S in the
middle of the catalyst can, between the first and second bricks.)
The new Integrated Air/Fuel Catalyst Monitor can be used to monitor the entire catalyst volume, even on LEV-II
vehicles.
Index ratios for ethanol (Flex fuel) vehicles vary based on the changing concentration of alcohol in the fuel. The
malfunction threshold typically increases as the percent alcohol increases. For example, a malfunction threshold of
0.5 may be used at E10 (10% ethanol) and 0.9 may be used at E85 (85% ethanol). The malfunction thresholds are
therefore adjusted based on the % alcohol in the fuel. (Note: Normal gasoline is allowed to contain up to 10%
ethanol (E10)).
Vehicles with the Index Ratio Method Using a Switching HO2S Sensor employ an Exponentially Weighted Moving
Average (EWMA) algorithm to improve the robustness of the catalyst monitor. During normal customer driving, a
malfunction will illuminate the MIL, on average, in 3 to 6 driving cycles. If KAM is reset (battery disconnected) or
DTCs are cleared, a malfunction will illuminate the MIL in 2 driving cycles. See the section on EWMA for additional
information.
The EWMA logic incorporates several important CARB requirements. These are:
Fast Initial Response (FIR): The first 4 tests after a battery disconnect or code clear will
process unfiltered data to quickly indicate a fault. The FIR will use a 2-trip MIL. This will help
the service technician determine that a fault has been fixed.
Step-change Logic (SCL): The logic will detect an abrupt change from a no-fault condition to
th
a fault condition. The SCL will be active after the 4 catalyst monitor cycle and will also use a
2-trip MIL. This will illuminate the MIL when a fault is instantaneously induced.
Normal EWMA (NORM): This is the normal mode of operation and uses an Exponentially
Weighted Moving Average (EWMA) to filter the catalyst monitor test data. It is employed after
th
the 4 catalyst test and will illuminate a MIL during the drive cycle where the EWMA value
exceeds the fault threshold. (1 trip MIL).
Starting in the 2010 ½ Model Year and later, the catalyst monitor will employ catalyst break-in logic. This logic will
prevent the catalyst monitor from running until after a catalyst break-in period.
The catalyst monitor will not run on a new vehicle from the assembly plant until 60 minutes of time above a catalyst
temperature (typically 800 to 1100 deg F) has been accumulated or 300 miles has elapsed.
New modules at the assembly plant will have an NVRAM flag initialized to delay the catalyst monitor. Service
modules and re-flash software will have the flag set to allow that catalyst monitor to run. The flag cannot be reset to
delay the catalyst monitor from running by any tool or service procedure.
The catalyst monitor results are converted to a ratio for Mode $06 reporting to keep the same look and feel for the
service technician. The equation for calculating the Mode $06 monitor result is:
Good catalyst reactivation fuel is intended to represent what the monitor would measure for a green catalyst.
** NOTE: In this document, a monitor or sensor is considered OK if there are no DTCs stored for that component
or system at the time the monitor is running.
The HEV uses the Low Data Rate misfire monitor. The LDR system is capable of meeting “full-range” misfire
monitoring requirements on 4-cylinder engines. The software allows for detection of any misfires that occur 6
engine revolutions after initially cranking the engine. This meets the new OBD-II requirement to identify misfires
within 2 engine revolutions after exceeding the warm drive, idle rpm.
The LDR Misfire Monitor uses a low-data-rate crankshaft position signal, (i.e. one position reference signal at 10
deg BTDC for each cylinder event). The PCM calculates crankshaft rotational velocity for each cylinder from this
crankshaft position signal. The acceleration for each cylinder can then be calculated using successive velocity
values. The changes in overall engine rpm are removed by subtracting the median engine acceleration over a
complete engine cycle. The crankshaft acceleration is then processed by two algorithms. The first is optimized for
detection of sporadic and single cylinder patterns of misfire; the second is optimized for multi-cylinder patterns. The
resulting deviant cylinder acceleration values are used in evaluating misfire in the “General Misfire Algorithm
Processing” section below.
The acceleration that a piston undergoes during a normal firing event is directly related to the amount of torque that
cylinder produces. The calculated piston/cylinder acceleration value(s) are compared to a misfire threshold that is
continuously adjusted based on inferred engine torque. Deviant accelerations exceeding the threshold are
conditionally labeled as misfires. A threshold multiplier is used during startup CSER to compensate the thresholds
for the reduction in signal amplitude during spark retard conditions.
The calculated deviant acceleration value(s) are also evaluated for noise. Normally, misfire results in a non-
symmetrical loss of cylinder acceleration. Mechanical noise, such as rough roads or high rpm/light load conditions,
will produce symmetrical, positive acceleration variations. A noise limit is calculated by applying a negative
multiplier to the misfire threshold. If the noise limit is exceeded, a noisy signal condition is inferred and the misfire
monitor is suspended for a brief interval. Noise-free deviant acceleration exceeding a given threshold is labeled a
misfire.
The number of misfires is counted over a continuous 200 revolution and 1000 revolution period. (The revolution
counters are not reset if the misfire monitor is temporarily disabled such as for negative torque mode, etc.) At the
end of the evaluation period, the total misfire rate and the misfire rate for each individual cylinder is computed. The
misfire rate evaluated every 200 revolution period (Type A) and compared to a threshold value obtained from an
engine speed/load table. This misfire threshold is designed to prevent damage to the catalyst due to sustained
excessive temperature (1650°F for Pt/Pd/Rh advanced washcoat and 1800°F for Pd-only high tech washcoat). If
the misfire threshold is exceeded and the catalyst temperature model calculates a catalyst mid-bed temperature
that exceeds the catalyst damage threshold, the MIL blinks at a 1 Hz rate while the misfire is present. If the misfire
occurs again on a subsequent driving cycle, the MIL is illuminated.
If a single cylinder is determined to be consistently misfiring in excess of the catalyst damage criteria, the fuel
injector to that cylinder will be shut off for 30 seconds to prevent catalyst damage. Up to two cylinders may be
disabled at the same time on 6 and 8 cylinder engines and one cylinder is disabled on 4 cylinder engines. This fuel
shut-off feature is used on all engines starting in the 2005 MY. After 30 seconds, the injector is re-enabled. If
misfire on that cylinder is again detected after 200 revs (about 5 to 10 seconds), the fuel injector will be shut off
again and the process will repeat until the misfire is no longer present. Note that ignition coil primary circuit failures
(see CCM section) will trigger the same type of fuel injector disablement.
The misfire rate is also evaluated every 1000 rev period and compared to a single (Type B) threshold value to
indicate an emission-threshold malfunction, which can be either a single 1000 rev exceedence from startup or four
subsequent 1000 rev exceedences on a drive cycle after start-up. Some vehicles will set a P0316 DTC if the Type
B malfunction threshold is exceeded during the first 1,000 revs after engine startup. This DTC is normally stored in
addition to the normal P03xx DTC that indicates the misfiring cylinder(s). If misfire is detected but cannot be
Profile Correction
"Profile correction" software is used to "learn" and correct for mechanical inaccuracies in the crankshaft position
o
wheel tooth spacing. Since the sum of all the angles between crankshaft teeth must equal 360 , a correction factor
can be calculated for each misfire sample interval that makes all the angles between individual teeth equal. . The
LDR misfire system will learn one profile correction factor per cylinder (ex. 4 correction factors for a 4 cylinder
engine), while the HDR system will learn 36 or 40 correction factors depending on the number of crankshaft wheel
teeth (ex. 36 for V6/V8 engines, 40 for V10 engines).
The corrections are calculated from several engine cycles of misfire sample interval data. The "mature" correction
factors are the average of a selected number of samples. In order to assure the accuracy of these corrections, a
tolerance is placed on the incoming values such that an individual correction factor must be repeatable within the
tolerance during learning. This is to reduce the possibility of learning corrections on rough road conditions which
could limit misfire detection capability and to help isolate misfire diagnoses from other crankshaft velocity
disturbances.
To prevent any fueling or combustion differences from affecting the correction factors, learning is done during
decel-fuel cutout. This can be done during closed-throttle, non-braking, de-fueled decelerations in the 60 to 40 mph
range after exceeding 60 mph (likely to correspond to a freeway exit condition). In order to minimize the learning
time for the correction factors, a more aggressive decel-fuel cutout strategy may be employed when the conditions
for learning are present and are typically learned in a single 60 to 40 MPH deceleration, but can be learned during
up to 3 such decelerations, or over a higher number of shorter duration decelerations..
For Hybrid Electric Vehicles profile is learned by using the electric drive to spin the crankshaft on the first engine
shutdown during which time profile is calculated.
Since inaccuracies in the wheel tooth spacing can produce a false indication of misfire, the misfire monitor is not
active until the corrections are learned. In the event of battery disconnection or loss of Keep Alive Memory the
correction factors are lost and must be relearned. If the software is unable to learn a profile after three 60 to 40
mph decels, or for HEV's after 6 failed attempts to learn, a P0315 DTC is set.
Neutral profile learning is used at End of Line to learn profile correction via a series of one or more neutral engine
rpm throttle snaps. This allows the Misfire Monitor to be activated at the Assembly Plant. A Test Tool command is
required to enable this method of learning, so this method will only be performed by a Plant or Service technician.
Learning profile correction factors at high-speed (3,000 rpm) neutral conditions versus during 60-40 mph decels
optimizes correction factors for higher rpms where they are most needed and eliminates driveline/transmission and
road noise effects. This improves signal to noise characteristics which means improved detection capability.
The profile correction factors learned at the Assembly Plant are stored into non-volatile memory. This eliminates
the need for specific customer drive cycles. However, misfire profiles may need to be relearned in the Service Bay
using a service procedure if major engine work is done or the PCM is replaced. (Re-learning is not required for a
reflash.)
The engine shutdown profile learning algorithm has been left active in the software as a backup.
Low Data Rate Measure Delta Measure Delta High Data Rate
Algorithm Time Intervals Time Intervals Algorithm
Calculate Calculate
Acceleration Acceleration
Pattern
Cancellation Filter
Cylinder Acceleration
Values
Misfire Detection
Generic Misfire Thresholds
Algorithm
Processing
Noisy Signal
Filtering
Emissions Test
(Type B Misfire)
(every 1000 revs)
Fault Codes,
MIL
Freeze Frame
For 2013 MY, a new family of Hybrid Electric Vehicles (HEV) will be introduced. Some of these vehicles will be
able to charge the battery by plugging the vehicle into the grid as well as using an engine –driven generator and
regenerative brakes to charge the battery while driving (Plug in Hybrid Electric Vehicles (PHEV)); others will only
be using an engine –driven generator and regenerative brakes to charge the battery while driving (Hybrid Electric
Vehicles (HEV)). For both types of vehicle, depending on the vehicle drive cycle, there could be very little or no
engine operation during the driving cycle. This poses a challenge as historically, evaporative system leak
diagnostics has relied on engine vacuum to evacuate the fuel tank and perform a large portion of the leak check
and purge flow diagnostics. Additionally, the Engine Off Natural Vacuum (EONV) test that runs after key off relies
on a exhaust system to heat up underbody components and reject heat into the fuel tank. It is the cooling of the
fuel in the tank that generates the vacuum that enables to EONV test to perform the 0.020" leak check. If the
engine does not run, both of the current engine-running and engine –off evap system diagnostics are not feasible.
In spite of this, the OBD-II regulations still require manufacturers to monitor the evaporative system for leaks and to
perform a functional purge flow check. One solution is to add a vacuum pump that can generate vacuum on
demand to facilitate the evaporative system diagnostics. The system that is being used is manufactured by the
Denso Corporation and is called Evaporative Leak Check Module (ELCM).
The ELCM consists of a vacuum pump, an absolute pressure sensor, a 0.020" reference orifice and a change-over
valve (COV). The 0.020" reference orifice is used to obtain a 0.020" reference every time the monitor is run. This
reference check becomes the threshold for passing or failing a 0.020" leak. Since the threshold is dynamically
established at the beginning of the test, many of the noise/control factors (e.g. fuel level, ambient temperature,
barometric pressure) are accounted for. The ELCM system is illustrated below:
ELCM
Ref Orifice
ELCM
COV Pressure Sensor
Filter
Atmosphere
Filter
Canister
Pump
COV Off
Atm
Canister
PS
Ref Orifice
Typical purge flow/fuel fill configuration. Yellow denotes the vacuum/pressure path.
COV Off
Atm
Canister
PS
Ref Orifice
Typical reference check configuration (Pump ON). Yellow denotes the vacuum path.
COV On
Atm
Canister
PS
Ref Orifice
Typical system leak check configuration (Pump On, COV On). Yellow denotes the vacuum path.
Pressure
Reference Pass/Fail
Check No Leak P check > P ref Threshold
Time
The ELCM leak detection test runs at key off if entry conditions such as vehicle soak, fuel level, ambient
temperature, BARO, etc. are satisfied. The test sequence begins with a pump warm-up time of 5 minutes followed
by a reference check calculation. Once the reference check is obtained, the pump is turned off which allows the
vacuum to equalize to atmosphere. The changeover valve is then energized and the Evap system is evacuated.
The pump stays on until the vacuum crosses the reference check threshold or the vacuum trace flat-lines above
the reference check threshold.
In addition to running leak diagnostics, the evap monitor also performs numerous functional tests on the individual
components that are used for the evap leak check, (i.e., stuck open/closed COV, stuck on/stuck off pump,
restricted orifice, stuck open/stuck closed Fuel Tank Isolation Valve, stuck closed Canister Purge Valve) The
monitor runs once per drive cycle during a key off condition and increments the Evap System IUMPR numerator
once the ghost monitor completes. Rate based completion frequency (IUMPR) is reported via J1979 Mode$09.
The ELCM system is used in sealed (PHEV) and non-sealed (HEV) evap systems. Although the algorithm
between sealed and non-sealed applications differs slightly (sealed system has FTIV while non-sealed has VBV),
the leak detection method remains the same.
HEVs use a traditional non-sealed evaporative system. This is because the engine is expected to run for extended
periods of time on an HEV so fuel vapors will get purged on a regular basis.
o Uses traditional Canister Purge Valve (CPV)
o Uses traditional Vapor Blocking Valve (VBV)
o Uses traditional (low pressure) Fuel Tank Pressure Transducer (FTPT)
o ELCM replaces Canister Vent Valve (CVV).
o VBV de-energized state is open
Plug in HEVs (PHEV) use a sealed evaporative system. The sealed fuel system is designed to contain fuel vapors
while not refueling. This is because the engine may not run for extended periods of time on a PHEV so fuel vapors
do not get purged on a regular basis. Internally, the sealed system is known as a NIRCOS (Non-Integrated
Refueling Canister Only System).
o Canister sized for refueling vapors only
o Uses a structurally improved steel fuel tank
o Tank pressure relief at -2.5 psi and 5.5 psi
o Requires an electric refueling system to relieve the pressure in the tank
o Uses traditional Canister Purge Valve (CPV)
o Uses High Pressure Fuel Tank Pressure Transducer (HPFTPT)
o Uses Fuel Tank Isolation Valve (FTIV) in place of Vapor Blocking Valve (VBV)
o FTIV de-energized state is closed
o When FTIV is closed, it splits the evap system into two separately diagnosable system – the "fuel tank
side" and the "fresh air side"
Fresh Air
Pump
ELCM
ELCMPS Canister Circuit
Ref Orifice 0.020"
Intake
Manifold
CPV
Carbon
Canister
NIRCOS:Integrated FTIV
Tank Circuit
FTIV HPFTPT
nonNIRCOS: VBV
Fuel Tank
VBV FTPT
The Canister Purge Valve (CPV) output circuit is checked for opens and shorts (P0443)
Note that a stuck closed CPV generates a P04ED, a leaking or stuck open CPV generates a P1450.
Note: there is a “Wait” period after key-off to ensure that ELCM pump temperature is within the specified operating
temperature. The “Wait” time is a function of ambient temperature (5 – 17 min).
The entry conditions for the engine off monitor are evaluated while the vehicle is being driven, prior to shut down.
Basic entry conditions for the leak diagnostics are a combination of conditions mandated by CARB and others
intended to make the monitor robust to false calls.
The first phase starts by obtaining a BARO reading. The PCM opens the CPV and vents any trapped vacuum.
After some stabilization time, with all the ELCM actuators in their unpowered state, the monitor obtains a BARO
reading.
Then the ELCM pump is turned on (COV not energized) to send flow through the reference orifice. If the slope of
the ELCMPS pressure is less than a threshold value, then the monitor tentatively infers that the COV is stuck in the
energized state and flow is not going through the reference orifice. This will set a P24C0 unless the pump
functional test fails later in the test. Once the COV functional test is complete, the orifice functional test is
performed. The stabilized ELCMPS pressure is compared to a threshold value to see if too much vacuum was
produced. This would be an indication of a clogged/restricted orifice. In this case, the monitor aborts and a P043E
DTC is set. The stabilized ELCMPS pressure is compared to a threshold value to see if too little vacuum was
produced. This would be an indication of a high flow orifice. In this case, the monitor aborts and a P043F DTC is
set. The last part of Phase 0 is the pump warm-up time (typically 5 min). Once the warm-up time is met, the
ELCMPS pressure is compared against a threshold to determine how much vacuum was generated across the
orifice during the warm-up time. Too little vacuum is an indication that the pump is stuck off in which case the
monitor aborts and sets P2401 DTC. If all tests pass, monitor goes on to Phase 1.
Note: The ELCMPS sensor is an absolute sensor whereas the HPFTPT is a relative sensor. To compare the two
sensors, the ELCMPS signal is converted to gauge by subtracting the BARO reading.
In Phase 1, the resulting ELCMPS relative pressure is averaged and stored as a 0.020" reference. This 1st
reference check is compared against a table of min and max reference pressures as a function of BARO. If the
reference pressure is outside the min and max, the monitor aborts and sets a P24B9 DTC. Then, the vacuum
pump is commanded off and the ELCMPS pressure is compared to atmospheric pressure. If the ELCMPS
pressure does not go back up above a threshold pressure, the monitor infers that the vacuum pump is stuck on,
aborts and sets a P2402 DTC. Otherwise, the monitor continues on with the next phase.
Phase 2 is the most critical phase in the ELCM monitor. This is where the Evap system (canister side only or the
entire system) is evacuated using the ELCM vacuum pump. The COV as well as the vacuum pump are turned on.
The COV stuck functional test is performed again to check whether the COV is stuck in the de-energized position.
The rate of change of the ELCMPS pressure is compared to a threshold. The monitor aborts and set a P24C1
DTC if the ELCMPS vacuum slope is too high. If the COV test passes, the monitor goes on to check the FTIV
valve for being stuck open. The rate of change of the ELCMPS pressure is calculated again and compared to a
threshold. If the slope is too low, the FTIV is inferred to be stuck open and the monitor aborts and sets a P2450
DTC. If the FTIV had been commanded open and the rate of change of the ELCMPS pressure is greater than a
threshold, then the FTIV is inferred to be stuck closed and the monitor aborts and sets a P2451 DTC.
The monitor periodically computes the slope of the pressure value. If the slope indicates that the signal is "flat
lining" without crossing the reference check threshold, the determination is that a leak is present, pending the vapor
generation analysis. If the signal "flat lines" for an HEV, the monitor sets a preliminary P0456 failure flag and goes
to Phase 5. For a PHEV, if the signal “flat lines”, the monitor sets a preliminary P04EF failure flag indicating a leak
on the fresh air side of the Evap system and the test goes on to Phase 3.
In Phase 3, the filtered tank pressure is evaluated to determine whether the tank is leak-free or not. If there is
sufficient pressure or vacuum buildup in the tank and the pressure/vacuum variation in the tank is low, the tank is
properly sealed and there are no leaks. In such a case, the FTIV is left in its normally closed position and only the
canister side of the Evap system is monitored for leaks. If the tank pressure/vacuum is near atmosphere or if the
tank pressure/vacuum is high but has considerable variation, then the FTIV is commanded open and the entire
Evap system is monitored for leaks. The monitor goes back to phase 2 to evacuate the entire Evap system.
If the monitor fails with the FTIV open, a fail flag is set to indicate a potential leak in the entire Evap system
(P04EE).
There are no abort conditions in this phase. Note that there is a delay to allow the pressure to stabilize to
atmospheric pressure between the tank and canister side checks.
Phase 4: Vapor Generation/CPV Stuck Closed (PHEV only, seal evap system)
This is the phase where the full Evap system is diagnosed for vapor generation in the case where a failure
occurred in the second Phase 2 while the FTIV was open. Vapor generation for the fuel results in a positive
pressure build up. It is typically caused by high RVP fuels and/or hot weather. The positive pressure can
overwhelm the vacuum being generated by the low flow ELCM pump. Depending on the magnitude of the vapors,
an otherwise sealed Evap system could be diagnosed as having a leak; therefore, the vapor generation check is
needed to qualify any leak monitor fail calls.
The vapor generation routine is based on the ideal gas law. The temperature is assumed to be constant during the
duration of the test. The volume is also assumed constant since the PHEV evap system uses a rigid, metal fuel
tank. Any pressure change is, therefore, due to fuel vapors. Phase 4 starts out by turning off the vacuum pump and
commands the COV to its vent position. With the FTIV open, the system is allowed to vent to atmosphere until the
pressure climbs to near atmosphere or times out. In the case of a timeout, the tank is assumed to have intense
vapors whereby even when it is open to atmosphere, the pressure is unable to equalize with atmospheric
pressure. Once the vented tank pressure is close to atmosphere, the FTIV is closed and the tank is sealed for a
calibrated time period. A positive pressure buildup more than a threshold value results in an abort and discarding
the fail call (i.e. a "no call"). In the case of a "pass" call in phase 2, the vapor generation test is not run.
This is the final phase in the ELCM monitor. The purpose of this phase is to validate that the 1st reference check is
accurate by obtaining a 2nd reference check and comparing the two. After some stabilization time, another BARO
reading is obtained and compared to the first BARO reading. If the BARO readings do not match within a
calibrated limit, the monitor aborts. If the BARO readings are consistent, the monitor continues by turning on the
nd
vacuum pump for a calibrated warm-up time. The 2 reference check is compared against a table of min and max
reference pressures as a function of BARO. If the reference pressure is outside the min and max, the monitor
aborts and sets a P24B9 DTC. If the reference check is OK, then the 1st and 2nd reference checks are compared
to each other. If they disagree by more than a calibrated limit, then the monitor aborts and sets a P24B9 DTC. If
the BARO readings and reference pressures are reliable, then any evap system failures determined previously are
confirmed.
Key On
Key Off
ELCM temperature
cool down period
Phase 0
BP reading, Pump warmup time, COV Abort
stuck closed, reference orifice clogged,
pump not running checks
Phase 1
Reference Orifice measurement
Reference Orifice out of range Abort
Pump stuck On
Phase 2
Vacuum pulldown
COV stuck open
FTIV stuck open/closed
Preliminary pass/fail determinationTank Tank
Pressure Evaluation pumpdown
Tank Fail Phase 3
Tank Evaluation
Goto Phase 2 if tank pressure/vacuum Abort
near atmosphere
Tank Pass
Phase 4
Abort
Vapor Generation (for fail cases only)
Tank Ok
Phase 5
Second BP reading Abort
Second reference check
1st-2nd BP compare
1st-2nd reference check compare
Final Pass/Fail Determination
Exit
Shutdown ECM
Additional malfunctions that are identified as part of the evaporative system integrity check are as follows:
The Canister Purge Valve (CPV) output circuit is checked for opens and shorts (P0443)
Note that a stuck closed CPV generates a P04ED, a leaking or stuck open CPV generates a P1450.
The Evap Fuel Tank Switching Valve (EVAPSV) control circuit is checked for opens and shorts (P2418). For the
PHEV, this component is the FTIV (Fuel Tank Isolation Valve). For the HEV, this component is the VBV (Vapor
Blocking Valve).
Note that a stuck closed Evap Switching Valve generates a P2451; a stuck open Evap Switching Valve generates
a P2450.
Note that for the PHEV, this component is the FTPTHP (Fuel Tank Pressure Transducer – High Pressure). For the
HEV, this component is the FTPT (Fuel Tank Pressure Transducer).
Finally, the Fuel Level Input is checked for noisy readings. If the FLI input changes from an in-range to out-of-range
value repeatedly, a P0461 DTC is set.
Different malfunction criteria are applied based on the range in which the fuel level sensor is stuck.
In the range between 6% and 93%, a 17.5% difference between fuel consumed.
The PHEV uses a pressurized evap system. In order to refuel the vehicle, the customer needs to push a fuel door
button in the cabin. This allows the PCM to both open a latch on the spring-loaded fuel fill door on the outside of
the vehicle to provide access to the fuel filler inlet and open an FTIV (Fuel Tank Isolation Valve) which vents the
evap system to the canister and allows refueling fuel vapors to enter the canister.
If the FTIV is not open, the evap system will vent when the customer pushes the fuel fill nozzle into the fuel fill inlet
and the customer will not be able to refuel the vehicle because the displaced vapors have no where to go).
Refuel Button
Refueling Process:
Customer presses “refuel button”
Signal is sent from BCM to PCM
PCM opens FTIV & reads FTPT
PCM sends cluster message “Please wait to refuel”
Once fuel pressure is relieved, PCM unlocks fuel door solenoid.
PCM sends cluster message “Ready to Refuel”
Customer dispenses fuel
Customer closes fuel door
PCM recognizes closed fuel door by switch state
FTIV closes
h/w
HS-CAN
The adaptive fuel strategy uses O2 sensors for fuel feedback. The fuel equation includes short and long term fuel
trim modifiers:
A conventional O2 sensor (not a wide-range sensor) can only indicate if the mixture is richer or leaner than
stoichiometric. During closed loop operation, short term fuel trim values are calculated by the PCM using oxygen
sensor inputs in order to maintain a stoichiometric air/fuel ratio. The PCM is constantly making adjustments to the
short term fuel trim, which causes the oxygen sensor voltage to switch from rich to lean around the stoichiometric
point. As long as the short term fuel trim is able to cause the oxygen sensor voltage to switch, a stoichiometric
air/fuel ratio is maintained.
When initially entering closed loop fuel, SHRTFT starts 1.0 and begins adding or subtracting fuel in order to
make the oxygen sensor switch from its current state. If the oxygen sensor signal sent to the PCM is greater than
0.45 volts, the PCM considers the mixture rich and SHRTFT shortens the injector pulse width. When the cylinder
fires using the new injector pulse width, the exhaust contains more oxygen. Now when the exhaust passes the
oxygen sensor, it causes the voltage to switch below 0.45 volts, the PCM considers the mixture lean, and
SHRTFT lengthens the injector pulse width. This cycle continues as long as the fuel system is in closed loop
operation.
O2 sensor voltage
O2 sensor voltage
O2 sensor voltage
O2 sensor voltage
As components continue to change beyond normal limits or if a malfunction occurs, the long-term fuel trim values
will reach a calibratable rich or lean limit where the adaptive fuel strategy is no longer allowed to compensate for
additional fuel system changes. Long term fuel trim corrections at their limits, in conjunction with a calibratable
deviation in short term fuel trim, indicate a rich or lean fuel system malfunction.
Note that in the PCM, both long and short-term fuel trim are multipliers in the fuel pulse width equation. Scan tools
normally display fuel trim as percent adders. If there were no correction required, a scan tool would display 0%
even though the PCM was actually using a multiplier of 1.0 in the fuel pulse width equation.
START
Engine conditions No
(O2 sensors warm, closed Monitor Entry
loop fuel requests) Conditions
Met?
Yes
SRTFT +
LONGFT >
threshold?
No
MIL
As the front UEGO sensor ages and gets exposed to contaminants, it can develop a rich or lean bias in its transfer
function. The rear bias control (also called FAOSC – Fore/Aft Oxygen Sensor Control) system is designed to
compensate for any of these bias shifts (offsets) using the downstream HO2S sensor. The "FAOS" monitor looks
for any bias shifts at the stoichiometric point of the front UEGO sensor lambda curve. If the UEGO has developed a
bias beyond the point for which it can be compensated for, lean (P2096, P2098) or rich (P2097, P2099) fault codes
will be set.
UEGO "FAOS
Monitor" Operation:
DTCs P2096 – Post catalyst fuel trim system too lean (Bank 1)
P2097 – Post catalyst fuel trim system too rich (Bank 1)
Monitor execution Continuous while in closed loop fuel
Monitor Sequence > 30 seconds time in lack of movement test, > 30 seconds time in lack of switch
test
Sensors OK ECT, IAT, MAF, MAP, VSS, TP, ETC, FRP, FVR, DPFE EGR, VCT, VMV/EVMV,
CVS, CPV, EVAPSV, FTP, CKP, CMP, ignition coils, injectors, no misfire DTCs,
no system failures affecting fuel, no EVAP gross leak failure, UEGO heaters OK,
rear HO2S heaters OK, no "lack of switching" malfunction, no "lack of movement"
malfunction, no UEGO circuit malfunction, no rear stream 2 HO2S circuit
malfunction, no rear stream 2 HO2S functional DTCs, no rear stream 2 HO2S
response rate malfunction.
Monitoring Duration 5 seconds to register a malfunction
The Air Fuel Imbalance Monitor is designed to monitor the cylinder-to-cylinder air fuel imbalance per engine bank.
When an Air Fuel (A/F) imbalance is present, the front UEGO signal becomes noisier. The monitor uses the high
frequency component from the UEGO signal as an indicator of A/F imbalance. "Hash" is the difference between
two consecutive front UEGO voltage samples. The UEGO signal is monitored continuously and a differential or
"hash" value is continuously calculated. When the hash is below a threshold, it is indicative of normal operation. If
the hash exceeds the threshold, an A/F imbalance is assumed which increments a hash error counter. The counter
accumulates hash during series of calibratable rpm windows. Typically, a single window consists of 50 engine
revolutions. A total rpm window counter calculates number of completed rpm windows. Monitor completion typically
requires 30 rpm windows. When the monitor completes, an A/Fuel imbalance index is calculated. The monitor
index is defined as the ratio of the failed rpm windows over the total rpm windows required to complete monitor. If
the monitor imbalance ratio index exceeds the threshold value, an A/F imbalance DTC is set.
1
VEGO11
0.9 VEGO12
0.8
VEGO11-Raw high frequency data
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0 5 10 15 20 25 30
Time
uego11
1.5
1
0 10 20 30 40 50 60 70
Time(sec)
0.4
diff ego11
0.2
u
0
0 10 20 30 40 50 60 70
Time(sec)
4000
uego11
0
0 10 20 30 40 50 60 70
400
Time(sec)
one rpm window
350
300
10 sec counter, error counter
250
200
150
100
50
0
0 2000 4000 6000 8000 10000 12000
Time(sec)
The UEGO sensor infers an air fuel ratio relative to the stoichiometric (chemically balanced) air fuel ratio by
balancing the amount of oxygen pumped in or out of a measurement chamber. As the exhaust gasses get richer or
leaner, the amount of oxygen that must be pumped in or out to maintain a stoichiometric air fuel ratio in the
measurement chamber varies in proportion to the air fuel ratio. By measuring the current required to pump the
oxygen in or out, the air fuel ratio (lambda) can be estimated. Note that the measured air fuel ratio is actually the
output from the UEGO ASIC pumping current controller and not a signal that comes directly from the sensor.
Pump
PC Current
M Measurement
Connector
Senso
r Measurement
IP Measured Resistor
Pumping Current (61.9 Ohm)
O Pumping Cell IA
- Trim Resistor
Exhaust (30 – 300 Ohm)
Diffusion Detection
Gasses IN
Passage Cavity 450 Total
O2, +
HC,CO O Nernst cell mV Pumping
- RE ref. -
NOx, H2… (EGO) +2.5V Current
Reference Air Virtual
Ground 20ma reference pump
Heater current
Impedance Measured
Measuremen Impedanc
H- t Heater e Groun
Control d
H+
B+
O2 Sensor
Voltage Heater YES
Monitor UEGO
circuits, Heater CKT Voltage and
voltage and current Current
Lack of
NO movement
suspected ?
Front O2
Sensor YES
Lambda
Time
Initiate Defib jump/ramp heater
NO
wave and monitor control
Time between Activity voltage at
O2 switches < NO
limit <
max? threshold?
Front O2
Sensor
Lambda Magnitude > NO
threshold ?
YES
YES
YES
Response
NO Test Entry YES
Conditions
Met? Modulate fuel request
and monitor voltage
UEGO ASIC or activity
smart driver
indicates NO
malfunction or
current < or > Magnitude > NO
Front O2 Sensor
threshold? voltage threshold ?
YES
END
YES
Fault management – MIL after 2 driving
cycles w/ malfunction MIL
The UEGO sensor also has a trim (IA) or label resistor (RL). The biggest source of part to part variability in the
measured air fuel ratio is difference in the diffusion passage. This source of variation is simply the piece-to-piece
differences from the manufacturing process. To compensate for this source of error, each sensor is tested at the
factory and a trim or label resistor is installed in the connector. The value of this resistor is chosen to correlate with
the measured difference between a particular sensor and a nominal sensor
For Bosch UEGO, the trim resistor is connected in parallel to the pumping current sense resistor and the pumping
current flows through both. The trim resistor adjusts the measured pumping current back to the expected nominal
value at any given air fuel ratio (correcting for the sensor to sensor variations in the diffusion passage). Small trim
resistors are required for sensors that require more pumping current at any particular lambda. Conversely, for
sensors with lower diffusion rates than average, less pumping current is required, so a higher than average
impedance trim resistor is installed. When IA circuit is open, all of the pumping current flows through the measuring
resistor which increases the measured voltage. Since the pumping current is amplified, the UEGO pumping current
to lambda transfer function will reflect the error. The slope of the UEGO sensor transfer function changes, which
results in the wrong output of the UEGO signal (the slope of the pumping current to lambda relationship can
increase or decrease). For "stoichiometric" air/fuel control applications, an open IA circuit is not monitored since the
lambda error is minimal in "stoichiometric" mode. A worst case (40 ohm resistor) open IA was tested on a 2008MY
3.5L Taurus PZEV and showed no impact on tailpipe emissions.
For "Non-Stoichiometric Closed Loop (NSCL)" air/fuel control applications, a continuous open IA diagnostics (Air
Rationality Test) is required since the lambda error is more significant in this mode. The air rationality test will
always monitor the UEGO sensor voltage reading during Decel Fuel Shut Off (DFSO) event. The monitor
compares the UEGO sensor voltage reading in air against the expected value for pure air. If the UEGO sensor
voltage during DFSO exceeds the maximum UEGO voltage in air threshold, then the fault timer increments. If the
fault timer exceeds the fault time threshold, then open IA DTC P2626 and/or P2629 will set. Since transient
sources of fuel in the exhaust after injector cut can contribute to the UEGO sensor voltage to read lower (rich), the
air rationality monitor will not call a pass until the transient sources of fuel have been exhausted and pure air entry
conditions during DFSO are met (i.e. all injectors must be off, purge must be off, no fuel must be leaking around
the PCV valve, and a few transport delays must have passed to allow the last fuel transients to be exhausted
leaving nothing for the sensor to see, but air).
UEGO equipped vehicles will also monitor the circuitry between the PCM and the UEGO sensor via the wire
diagnostics capability included on the UEGO ASIC chip. The wire diagnostics will detect wires (IP, IA, VM/COM,
RE/VS) shorted to battery, or ground, and in most cases will detect open circuits (IP, VM/COM, RE/VS). The
diagnostic bits are transmitted to the PCM via SPI (serial peripheral interface). The SPI communication is validated
continuously, and if a SPI communication failure is detected, fault code(s) P064D and/or P064E will be set. The
ASIC is also capable of detecting internal circuitry failure; in which case, an ASIC failure DTC (P1646, P1647)
along with the SPI communication failure DTC (P064D, P064E) will be set.
Typical UEGO “Lack of Movement – Open Pump Current Circuit " entry conditions
(Bosch UEGO only):
Entry condition Minimum Maximum
Closed Loop or Open Loop Requested due to UEGO sensor fault
Constant lambda near stoich (~1) 0.99 1.01
Time since no lambda activity seen since start up 30 sec
Time since no lambda activity during intrusive Stream 1 response monitor 3 sec
o
Inferred Ambient Temperature - 40 F
Injector fuel pulsewidth 650 usec
UEGO ASIC not in recalibration mode
No air passing through during valve overlap (scavenging).
Battery Voltage 11.0 Volts 18.0 Volts
Typical UEGO “Lack of Movement – Open Pump Current Circuit” malfunction thresholds
(Bosch UEGO only):
Stage 1: > 20 seconds in test conditions without lambda movement during fuel control and reference current
"defib" while in closed loop fuel and < = 0.05 change in lambda movement.
Stage 2: < 0.2 seconds without lambda movement since startup for > 30 seconds in test conditions during
reference current "defib" while open loop fuel is requested due to UEGO sensor fault and < = 0.05 change in
lambda movement.
Typical UEGO “Lack of Movement – Open Reference Ground Circuit " entry conditions
(Bosch UEGO only):
Entry condition Minimum Maximum
Closed Loop or Open Loop Requested due to UEGO sensor fault
Constant lambda near stoich (~1) 0.99 1.01
Time since no lambda activity seen since start up 30 sec
Time since no lambda activity during intrusive Stream 1 response monitor 3 sec
Injector fuel pulsewidth 650 usec
UEGO ASIC not in recalibration mode
No air passing through during valve overlap (scavenging).
Battery Voltage 11.0 Volts 18.0 Volts
Typical UEGO “Lack of Movement – Open Reference Ground Circuit” malfunction thresholds
(Bosch UEGO only):
Stage 1: > 20 seconds in test conditions without lambda movement during fuel control and reference current
"defib" while in closed loop fuel and > 0.05 change in lambda movement.
Stage 2: > 20 seconds in test conditions without lambda movement during reference current "defib" while
open loop fuel is requested due to UEGO sensor fault and > 0.05 change in lambda movement.
The front UEGO monitor also detects malfunctions on the UEGO sensor such as reduced response or delayed
response that would cause vehicle emissions to exceed 1.5x the standard (2.5x the standard for PZEV). The
response rate is evaluated by entering a special 0.5 Hz square wave, fuel control routine. This routine drives the
air/fuel ratio around stoichiomentry at a calibratable frequency and magnitude, producing predictable oxygen
sensor signal amplitude.
A UEGO slow or delayed sensor will show an increased response time which is compared to a no-fault polygon.
Combinations of the rich to lean and lean to rich response times that fall outside the polygon indicate a sensor
malfunction (P0133 Bank 1).
Threshold (red) and No-Fault (green) data vs. No Fault Zone (Bank 1)
-0.2
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4
Lean to Rich Response Time, sec
The UEGO heater is controlled as a function of the measured impedance to keep the sensor at a near constant
temperature (Bosch: 780 deg C, NTK: 800 deg C). The impedance of the Nernst cell decreases as the sensor
temperature increases. This impedance is measured by periodically applying a small current across the Nernst cell
and measuring the change in the voltage. The output voltage is then sent to an A/D input on the PCM. After a cold
start, the UEGO heater ramps up to the maximum duty cycle to heat the sensor. After a few seconds, the
measured impedance will start to decrease and when the target value is crossed, the heater goes into closed loop
heater control to maintain the sensor at a near constant temperature.
The "UEGO Heater Temperature Control Monitor" tracks the time at the maximum duty cycle during the open loop
sensor warm up phase. If the measured impedance does not come down to the target value to allow the system to
transition from open loop heater control to closed loop heater control within a specified time, then a fault code is
set. This monitor also sets a malfunction when the closed loop heater control reaches a maximum or minimum
value for a period of time indicating that the controller is no longer able to maintain the target temperature,
however, if the inferred exhaust temperature is high enough that the sensor will be above the target temperature
even with no heat, then this monitor is disabled.
The UEGO heaters are also monitored for proper voltage and current. A UEGO heater voltage fault is determined
by turning the heater on and off and looking for corresponding voltage change in the heater output driver circuit in
the PCM.
A separate current-monitoring circuit monitors heater current once per driving cycle. This monitor normally runs in
closed loop heater control after all the exhaust gas sensor functional tests are completed, however, it can also run
intrusively. When the UEGO sensor indicates cold, but the heater is inferred to have been adequately warm, the
current monitor is forced to run intrusively prior to the completion of the heater temperature control monitor. The
heater current is actually sampled three times. If the current value for two of the three samples falls below or above
a calibratable threshold, the heater is assumed to be degraded or malfunctioning. (Multiple samples are taken for
protection against noise on the heater current circuit.)
O2 Sensor Voltage
Heater Voltage and YES
Monitor UEGO
circuits, Heater CKT Current
voltage and current
NO Lack of
movement
suspected ?
Front O2
Sensor YES
Lambda
Time
Initiate Defib jump/ramp heater
NO
wave and monitor control
Time between NO Activity voltage at
O2 switches < limit <
max? threshold?
NO Response Test
Entry Conditions
Met? YES
Modulate fuel request and
monitor voltage activity
UEGO ASIC
or smart driver NO
Front O2 Sensor
indicates Voltage O2 Sensor Voltage
malfunction or Or Magnitude > threshold ? NO
current < or > Front O2 Sensor Or
threshold? Response Time O2 Sensor Response
Time < threshold ?
YES
END
YES
Fault management – MIL after 2 driving
cycles w/ malfunction MIL
A functional test of the rear HO2S sensors is done during normal vehicle operation. The peak rich and lean
voltages are continuously monitored. Voltages that exceed the calibratable rich and lean thresholds indicate a
functional sensor. If the voltages have not exceeded the thresholds after a long period of vehicle operation, the
air/fuel ratio may be forced rich or lean in an attempt to get the rear sensor to switch. This situation normally occurs
only with a green catalyst (< 500 miles). If the sensor does not exceed the rich and lean peak thresholds, a
malfunction is indicated.
2005 MY and beyond vehicles will monitor the rear HO2S signal for high voltage, in excess of 1.1 volts and store a
unique DTC. (P0138, P0158). An over voltage condition is caused by a HO2S heater or battery power short to the
HO2S signal line.
Some Partial Zero Emission Vehicles (PZEV Focus) may utilize three sets of HO2S sensors. The front sensors
(HO2S11/HO2S21) are the primary fuel control sensors. The next sensors downstream in the exhaust are utilized
to monitor the light-off catalyst (HO2S12/HO2S22). The last sensors downstream in the exhaust
(HO2S13/Ho2S23) are utilized for very long term fuel trim in order to optimize catalyst efficiency (Fore Aft Oxygen
Sensor Control). Ford's first PZEV vehicle uses a 4-cylinder engine so only the Bank 1 DTCs are utilized.
The catalyst monitor tracks and uses the length of the rear HO2S signal. The rear HO2S is also known as the
Catalyst Monitor Sensor (CMS). As the catalyst ages, air/fuel fluctuations begin to break through the catalyst and
the length of this signal increases. Eventually the length of the CMS signal becomes long enough to identify a
failure for the catalyst monitor.
When an HO2S sensor degrades, it's response to air/fuel fluctuations slows down. The effect of a slow rear
HO2S sensor on the catalyst monitor is to reduce the length of the signal. A slow CMS sensor, therefore, may
cause the catalyst monitor to incorrectly pass a failed catalyst. The purpose of the Rear DFSO Response
diagnostic is to ensure the catalyst monitor has a valid CMS sensor with which to perform the catalyst monitor
diagnostic. The monitor is set to trigger at the level of degradation that will cause the catalyst monitor to falsely
pass a malfunction threshold catalyst.
The OBD-II regulations require this monitor to utilize Decel Fuel Shut Off (DFSO). Ford plans to aggressively use
DFSO starting in the 2009 MY on many applications to improve fuel economy. The DFSO rear O2 response test
will be phased in coincident with this feature.
The main part of the test is the measured rich to lean response rate. It is determined by a "slew" rate calculation
which determines the rich to lean slope of the sensor during a Decel Fuel Shut Off (DFSO) event which occurs
during closed pedal at vehicle speeds higher than 28 mph. The calculation for the slew rate (mV/sec) is illustrated
below.
0.7
CMS P1
Voltage
0.6
T3 P2
Interpolated
0.5 Rich Crossing CMS
Point Slew Rate
Voltage .
-6.51
0.4
T4
0.3
Interpolated Lean
Crossing Point
P3
0.2
P4
0.1
0
2.5 2.55 2.6 2.65 2.7 2.75
CMS_DFSO_TMR (sec)
1. Interpolate between points P1 and P2 to determine the time at which the rich limit threshold of 0.6 volts was
crossed.
2. Interpolate between points P3 and P4 to determine the time at which the lean limit threshold of 0.2 volts was
crossed.
3. Use the Interpolated times and the thresholds to calculate the slope or "slew rate" of the CMS sensor from 0.6
to 0.2 volts.
Time (sec)
The bottom half of the graph shows a CMS signal with black lines and a "Tx" number representing all of the
points of interest where the monitor captures data.
The slope or slew rate of the CMS sensor going from rich to lean is a negative number with the units of
mVolts/sec. The measured slew rate changes as an O2 sensor degrades, but it will also change as a function of
catalyst oxygen storage/age; therefore, the slew rate is normalized using an offset based on catalyst oxygen
storage/age. The catalyst oxygen storage/age is calculated by integrating the level of oxygen mass in the exhaust
stream from the time the injectors turn off to the time where the slew rate calculation begins. The fault line (red
line in the chart below) is calibrated to 80% of the fault distribution for various levels of oxygen storage/catalyst
age. As shown below, the integrated oxygen mass becomes smaller with catalyst age.
The final output of the monitor = the measured slew rate – normalized fault line, therefore, any positive number
will represent a fault. For the step change logic the fault threshold will represent 50% of the failed distribution (~
0.3).
Offset = -8.4
2.5 function of O2
Offset = -4.4
mass @ T3.
2
1
Offset = 1.49
0.5
0
-14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0
Slew Rate
Fault Detection O2 Mass Example Points
Due to the fact that intrusively driving the CMS sensor rich will cause drivability and emission concerns, there are
other several condition counters that have to fail prior to intrusively forcing the sensor to go rich. The sequence of
events to get to the rich failure is shown below:
Initially, in order to avoid excess emissions, the monitor will only run if the CMS voltage is rich (> 0.6
volts) or CMS sensor is transitioning from lean to rich (large positive slope . 0.2).
o Successive failures are counted up; when the count exceeds 5 to 10 failures the monitor will
now intrusively force rich fuel to run the test.
In order to avoid a drivability issues as a result of a lean shifted bank, the first phase of intrusive
control has a short time out (1 to 2 seconds).
o Successive failures are counted up; when the count exceeds 3 failures the monitor will now
intrusively force rich fuel to failure or a rich sensor.
All controllable measures have failed to force the sensor to switch, so the strategy will drive rich until
the sensor switches or the failure time out is exceeded (5 to 10 seconds).
o Successive failures are counted up; when the count exceeds 3 failures the monitor will now
set a fault (P013E for bank 1 or P014A for bank 2).
If the sensor is stuck rich (can't get lean) the fault procedure is:
While the injectors remain off, the sensor must get lean (<0.1 volts) prior to the failure time which must
be set to account for a green catalyst (5 to 10 seconds).
o Successive failures are counted up; when the count exceeds 3 failures the monitor will now
set a fault (P013E for bank 1 or P014A for bank 2).
The EWMA logic incorporates several important CARB requirements. These are:
Fast Initial Response (FIR): The first 4 tests after a battery disconnect or code clear will
process unfiltered data to quickly indicate a fault. The FIR will use a 2-trip MIL. This will help
the service technician determine that a fault has been fixed.
Step-change Logic (SCL): The logic will detect an abrupt change from a no-fault condition to
a fault condition. The SCL will be active after the 4th DCMS monitor cycle and will also use a
2-trip MIL. This will illuminate the MIL when a fault is instantaneously induced.
Normal EWMA (NORM): This is the normal mode of operation and uses an Exponentially
Weighted Moving Average (EWMA) to filter the EONV test data. It is employed after the 4th
EONV test and will illuminate a MIL during the drive cycle where the EWMA value exceeds
the fault threshold. (1 trip MIL).
The HO2S heaters are monitored for proper voltage and current. A HO2S heater voltage fault is determined by
turning the heater on and off and looking for corresponding voltage change in the heater output driver circuit in the
PCM.
A separate current-monitoring circuit monitors heater current once per driving cycle. The heater current is actually
sampled three times. If the current value for two of the three samples falls below a calibratable threshold, the
heater is assumed to be degraded or malfunctioning. (Multiple samples are taken for protection against noise on
the heater current circuit.)
The Electric Stepper Motor EGR System uses an electric stepper motor to directly actuate an EGR valve rather
than using engine vacuum and a diaphragm on the EGR valve. The EGR valve is controlled by commanding
from 0 to 52 discreet increments or “steps” to get the EGR valve from a fully closed to fully open position. The
position of the EGR valve determines the EGR flow. Control of the EGR valve is achieved by a non-feedback,
open loop control strategy. Because there is no EGR valve position feedback, monitoring for proper EGR flow
requires the addition of a MAP sensor.
Map
Sensor
Stepper Motor Intake Manifold
EGR Valve
0403
0400
Note: Some configurations may differ slightly
Exhaust
Gates
The stepper motor electrical test is a continuous check of the four electric stepper motor coils and circuits to the
PCM. A malfunction is indicated if an open circuit, short to power, or short to ground has occurred in one or more
of the stepper motor coils for a calibrated period of time. If a malfunction has been detected, the EGR system will
be disabled, and additional monitoring will be suspended for the remainder of the driving cycle, until the next
engine start-up.
EGR flow is monitored using an analog Manifold Absolute Pressure Sensor (MAP). If a malfunction has been
detected in the MAP sensor, the EGR monitor will not perform the EGR flow test.
The MAP sensor is checked for opens, shorts, or out-of-range values by monitoring the analog-to-digital (A/D)
input voltage.
The PCV valve is installed into an oil separator that is bolted to the side of the block. The PCV valve is designed
to last the full useful life of the engine and is not designed to be removed from the oil separator. The PVC valve is
connected to the intake manifold hose using a quick connect. Because the PCV valve cannot be removed from
the oil separator, the quick connect will be disconnected in the event vehicle service is required. Molded plastic
lines are used from the PCV valve to the intake manifold. The diameter of the lines and the intake manifold have
been increased to 0.625" so that inadvertent disconnection of the quick connect will cause either an immediate
engine stall or will not allow the engine to be restarted. The crank case ventilation hose on the cam cover is
connected to the air induction system using quick connects. The cam cover also incorporates an oil separator.
In the event that the vehicle does not stall if the line between the intake manifold and PCV valve is disconnected,
the vehicle will have a large vacuum leak that will cause the vehicle to run lean at idle. This will illuminate the MIL
after two consecutive driving cycles and will store one or more of the following codes: Lack of O2 sensor
switches, Bank 1 (P2195), Fuel System Lean, Bank 1 (P0171).
For the 2009 MY, the thermostat test has been enhanced to reduce the time it takes to identify a malfunctioning
thermostat. The enhanced monitor includes a model which infers engine coolant temperature.
During a cold start, when the thermostat should be closed, the monitor uses a model of ECT to determine
whether actual ECT should have crossed the Warm Up Temperature (WUT) threshold.
Once the ECT model exceeds the thermostat regulating temperature for 3 seconds, measured ECT is compared
to the WUT threshold to determine if ECT has warmed up enough. If ECT has warmed up to at least the WUT
threshold, the thermostat is functioning properly. If ECT is too low, the thermostat is most likely stuck open and a
P0128 is set.
engt_thms_reg_temp
(tstat regulating temp)
Coolant Temp (deg. F.)
fnengt_warm_eng_temp
(malfunction threshold)
time (sec)
Call Delay:
engt_call_dly_tm
(call is made when inferred ect
has exceeded regulating
temperature for this length of time)
The WUT threshold is normally set to 20 degrees F below the thermostat regulating temperature.
There are two features that are used to prevent a false thermostat diagnosis. For vehicles with dual heaters, the
WUT threshold is reduced at cold ambient temperatures below 50 deg F. For cases where the engine is not
producing sufficient heat, a timer is used to track time at idle or low load conditions (e.g. decels). If the ratio of
time at idle/low load versus total engine run time exceeds 50% at the time the fault determination is made, the
thermostat diagnostic does not make a fault determination for that driving cycle, i.e. "no-call".
The cooling system in the Plug-in Hybrid has been designed to include two functional cooling loops. This system is
designed to maximize cooling efficiency when the vehicle is running on either the gas engine or the electric motor.
The system operates in one of two different modes.
The first mode is the main or "combined" cooling loop mode which provides coolant flow through both the gas
engine and the cabin heater core. While in this loop, both the gas engine and an electric heater can be used to
maximize the heat transfer to the coolant thus providing both an increase in the engine metal temperature and heat
for the vehicle cabin.
The second cooling mode is the "isolated" loop mode where coolant flow through the cabin heater core is isolated
from the engine block. This loop is intended to provide cabin heat when the gas engine is not running. Coolant flow
is maintained in the "combined" loop by default (isolation valve de-energized), and by energizing the isolation valve
coolant flow is maintained in the "isolated" loop.
Coolant Temp
Degas ECT_eWP Sensor ECT2
Bottle eWP sensor signal
Electric Heater
Heater
Degas Return Core
CHT
Inlet Aux
Heater
Radiator DM58-8005-A
Pump
Fan DM58-8C607- A
Elec
Water Engine
Pump 2.0L Atk HEV
Check Valve
EGR
Valve
T-Stat
Bypas
Coolant
Outlet
While in the "combined" cooling loop, coolant flow is maintained by a PCM-controlled Engine Coolant Pump
(internally known as the electric Water Pump (eWP)). The Engine Coolant Pump is a pulse width modulated pump
that can be used to control coolant flow rates independent of engine speed. This allows the PCM to maximize fuel
economy by minimizing cooling system power consumption as compared to a traditional belt-driven water pump.
Additionally, it can be used to improve engine metal temperature heating/cooling rates. Even though the Engine
Coolant Pump can provide coolant flow while the engine is off, it's primary purpose is to provide coolant flow while
the engine is running. A low power consumption auxiliary water pump in the "isolation" loop is the primary source of
coolant flow for cabin heating when the vehicle is operating in electric mode.
Below is a summary of the diagnostics associated with the Engine Coolant Pump. Circuit faults for the LIN bus and
ERI lines are detected by the PCM while the pump power and ground line faults are detected by the Engine
Coolant Pump Control Module and communicated to the PCM through the LIN bus line. All mechanical faults are
detected by the Engine Coolant Pump Control Module and also communicated to the PCM over the LIN bus.
The Engine Coolant Pump speed is controlled by the PCM and communicated to the Engine Coolant Pump
Control Module over the LIN bus. A LIN bus communication fault (U019F) is set when the engine coolant pump
speed echoed back from the Engine Coolant Pump Control Module doesn't match the desired speed sent from the
PCM (requires no other electric water pump faults exist).
Typical Engine Coolant Pump Emergency Run Input check malfunction thresholds:
Difference between ERI state reported by ECPCM and actual ERI state at PCM
The Engine Coolant Pump power and ground line status is not communicated to the PCM by Engine Coolant
Pump Control Module. Therefore, the status of these lines is inferred by the PCM. If either of these lines is faulted,
the Engine Coolant Pump will not run, and there will no LIN bus communications from the Engine Coolant Pump
Control Module to the PCM. The PCM first checks to see if a fault on the communication line (U019F). If the
communication line is faulted and the engine coolant temperature is increasing then it is assumed that the pump is
not running and a P26D3 DTC is set. If the engine coolant temperature is not increasing then the PCM identifies
the communications fault only.
Electric Water Pump Control Module Power/Ground Signal Fault malfunction thresholds:
o
LIN bus comm. fault (U019F) and accumulated engine coolant temp increase > 10 C
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 100 OF 179
The Engine Coolant Pump Control Module can use the rpm feedback and current feedback to detect mechanical
faults for a blocked impeller and a "dry run" condition, i.e. loss of coolant. These conditions are communicated back
to the PCM over the LIN bus.
The Engine Coolant Pump Control Module communicates the control module electronics voltage and temperature
over the LIN bus to the PCM. The voltage is compared to the PCM system voltage to set DTCs P26D0 and
P26D1. The temperature signal is checked for out-of-range high which sets a P26D2 DTC.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 101 OF 179
Cold Start Emission Reduction Component Monitor
Engine Speed and Spark Timing Component Monitor (2010 MY and beyond)
The System Monitor and 2010 Component Monitor share the same entry conditions and monitor flow. During the
first 15 seconds of a cold start, the monitor checks the entry conditions, counts time in idle, observes catalyst
temperature, calculates the average difference between desired and actual engine speed, and calculates the
average difference between desired and commanded spark.
If the expected change in catalyst temperature is large enough, the monitor then begins the waiting period, which
lasts until 300 seconds after engine start. This 5-minute wait allows time to diagnose other components and
systems that affect the validity of the test. During this waiting period, there are no constraints on drive cycle and
the monitor cannot be disabled without turning off the key.
If the System monitor result falls below its threshold and all of the Component monitor results are below their
respective thresholds, the monitor determines whether the idle time was sufficient. If so, it considers the tests a
pass and the monitor is complete. If idle time was not sufficient, the monitor does not make a pass call and does
not complete. This prevents tip-ins from resulting in false passes.
Once the waiting period is complete, the monitor compares the average difference between desired and actual
engine speeds to a calibratable threshold that is a function of ECT at start. If the magnitude of the discrepancy
exceeds the threshold, P050A is set.
Once the waiting period is complete, the monitor compares the average difference between desired and
commanded spark to a calibratable threshold that is a function of ECT at start. If the magnitude of the discrepancy
exceeds the threshold, P050B is set.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 102 OF 179
TYPICAL CSER COMPONENT MONITOR ENTRY AND COMPLETION CONDITIONS
Entry condition Minimum Maximum
Barometric Pressure 22 in. Hg
Engine Coolant Temperature at Start 35 °F 100 °F
Catalyst Temperature at Start 35 °F 125 °F
Fuel Level 15%
BARO 22.5" Hg
No Torque Reduction by Injector Cutout
Power Takeout Not Active
Completion condition Minimum Maximum
Length of Time Entry Conditions are Satisfied 11 sec.
Expected Change in Catalyst Temperature 50 °F
Time in Idle 10 sec.
Selected Gear Neutral Drive
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 103 OF 179
Cold Start Variable Cam Timing Monitor (2008 MY and beyond)
If the VCT cam phasing is used during a cold start to improved catalyst heating, the VCT system is checked
functionally by monitoring the closed loop cam position error correction. If the proper cam position cannot be
maintained and the system has an advance or retard error greater than the malfunction threshold, a cold start
emission reduction (CSER) VCT control malfunction is indicated (P052A/P052B (Bank 1), P052C/P052D (Bank2).
This test is the same test that was used previously for monitoring the VCT system under Comprehensive
Component Monitoring requirements.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 104 OF 179
Cold Start Emission Reduction System Monitor
The Cold Start Emission Reduction System Monitor is being introduced for the 2007 MY on vehicles that meet the
LEV-II emission standards. The System Monitor detects the lack of catalyst warm up resulting from a failure to
apply sufficient CSER during a cold start. It does this by using the inferred catalyst temperature model to
determine how closely the actual catalyst temperature follows the expected catalyst temperature during a cold
start. How closely the actual temperature follows the expected temperature is reflected in a ratio which is
compared with a calibratable threshold.
Temperatures Used
The actual catalyst temperature is the same inferred catalyst temperature that is used by other portions of the
engine control system, including the CSER control system. The inputs to this actual temperature are measured
engine speed, measured air mass, and commanded spark.
The expected catalyst temperature is calculated using the same algorithm as the actual catalyst temperature, but
the inputs are different. Desired engine speed replaces measured engine speed, desired air mass replaces
measured air mass, and desired cold start spark replaces commanded spark. The resulting temperature
represents the catalyst temperature that is expected if CSER is functioning properly.
Ratio Calculation
A ratio is calculated to reflect how closely the actual temperature has followed the expected temperature. This
ratio is the difference between the two temperatures at a certain time-since-start divided by the increase in
expected temperature over the same time period. The ratio, then, provides a measure of how much loss of
catalyst heating occurred over that time period.
This ratio correlates to tailpipe emissions. Therefore applying a threshold to it allows illumination of the MIL at the
appropriate emissions level. The threshold is a function of ECT at engine start.
During the first 15 seconds of a cold start, the monitor checks the entry conditions, counts time in idle, and
observes catalyst temperature.
If the expected change in catalyst temperature is large enough, the monitor calculates the ratio as described
above. Otherwise the monitor does not make a call.
The monitor then begins the waiting period, which lasts from the time the ratio is calculated (15 seconds after
engine start) until 300 seconds after engine start. This 5-minute wait allows time to diagnose other components
and systems that affect the validity of the catalyst temperature model. During this waiting period, there are no
constraints on drive cycle and the monitor cannot be disabled without turning off the key.
At the end of the waiting period, if no other faults that could compromise the validity of the catalyst temperature
model are found, the monitor compares the ratio to the threshold.
If the ratio exceeds the threshold, the monitor considers the test a fail, and the monitor is complete.
If the ratio falls below the threshold, and all of the component monitor results are below their respective thresholds,
the monitor determines whether the idle time was sufficient. If so, it considers the test a pass and the monitor is
complete. If idle time was not sufficient, the monitor does not make a pass call and does not complete. This
prevents tip-ins from resulting in false passes.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 105 OF 179
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 106 OF 179
CSER SYSTEM MONITOR OPERATION
DTC P050E: Cold Start Engine Exhaust Temperature Too Low
Monitor Execution Once per driving cycle, during a cold start
Monitor Sequence Monitor data collection takes place during first 15 seconds of cold start
Sensors OK No fault is present in any of the sensors or systems affecting the catalyst
temperature model: Mass Air Flow (P0102, P0103), Throttle Position (P0122,
P0123, P0222, P0223), Misfire (P0316, P0300-P0312), Injectors (P0201-
P0212), Fuel System (P0171, P0172, P0174, P0175), Secondary Air (P0412,
P2258), Crank Position Sensor (P0320), Ignition Coil (P0351-P0360), Intake
Air Temp (P0112, P0113), Engine Coolant Temp/Cylinder Head Temp
(P0117, P0118, P1289, P1290), Variable Cam Timing (P0010, P0020, P0011,
P0012, P0021, P0022), Intake Manifold Runner Control (P2008).
Monitoring Duration Monitor completes 300 seconds after initial engine start
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 107 OF 179
Variable Cam Timing System Monitor
Variable Cam Timing (VCT) enables rotation of the camshaft(s) relative to the crankshaft (phase-shifting) as a
function of engine operating conditions. There are four possible types of VCT with DOHC engines:
With Exhaust Only VCT, the exhaust camshaft is retarded at part throttle to delay exhaust valve closing for
increased residual dilution and to delay exhaust valve opening for increased expansion work.
With Intake Only VCT, the intake camshaft is advanced at part throttle and WOT (at low to mid-range engine
speeds) to open the intake valve earlier for increased residual dilution and close the intake valve earlier in the
compression stroke for increased power. When the engine is cold, opening the intake valve earlier warms the
charge which improves fuel vaporization for less HC emissions; when the engine is warm, the residual burned
gasses limit peak combustion temperature to reduce NOx formation.
With Dual Equal VCT, both intake and exhaust camshafts are retarded from the default, fully advanced position to
increase EGR residual and improve fuel economy by reducing intake vacuum pumping losses. The residual
charge for NOx control is obtained by backflow through the late-closing exhaust valve as the piston begins its
intake stroke.
The VCT system hardware consists of a control solenoid and a pulse ring on the camshaft. The PCM calculates
relative cam position using the CMP input to process variable reluctance sensor pulses coming from the pulse ring
mounted on the camshaft. Each pulse wheel has N + 1 teeth where N = the number of cylinders per bank. The N
equally spaced teeth are used for cam phasing; the remaining tooth is used to determine cylinder # 1 position.
Relative cam position is calculated by measuring the time between the rising edge of profile ignition pickup (PIP)
and the falling edges of the VCT pulses.
The PCM continually calculates a cam position error value based on the difference between the desired and actual
position and uses this information to calculate a commanded duty cycle for the VCT solenoid valve. When
energized, engine oil is allowed to flow to the VCT unit thereby advancing and retarding cam timing. The variable
cam timing unit assembly is coupled to the camshaft through a helical spline in the VCT unit chamber. When the
flow of oil is shifted from one side of the chamber to the other, the differential change in oil pressure forces the
piston to move linearly along the axis of the camshaft. This linear motion is translated into rotational camshaft
motion through the helical spline coupling. A spring installed in the chamber is designed to hold the camshaft in the
low-overlap position when oil pressure is too low (~15 psi) to maintain adequate position control. The camshaft is
allowed to rotate up to 30 degrees.
Although the VCT system has been monitored under Comprehensive Component Monitoring requirements for
many years, a new, emission-based VCT monitor is being introduced for the 2006 MY on vehicles that meet LEV-II
emission standards. The intent of the new VCT monitoring requirements is to detect slow VCT system response
that could cause emissions to increase greater than 1.5 * std. in addition to detecting functional problems (target
errors).
The new logic calculates the instantaneous variance in actual cam position (the squared difference between actual
cam position and commanded cam position), then calculates the long term variance using a rolling average filter
(Exponentially Weighted Moving Average). Continued, slow response from the VCT system will eventually
accumulate large variances.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 108 OF 179
This same logic will also detect target errors that were detected by the previous CCM monitor. If the VCT system is
stuck in one place, the monitor will detect a variance which will quickly accumulate.
There are three variance indices that monitor cam variance in the retard direction, the advance direction, and for V-
engines, the difference between banks. If any variance index is greater than the malfunction threshold, a VCT slow
response/target error malfunction will be indicated (P0011, P0012 Bank 1, 0021, P0022 Bank 2). Target errors will
tend to generate only a single over-advanced or over-retarded code while slow response will tend to generate both
codes.
In addition, logic has been added to determine whether the camshaft and crankshaft are misaligned by one or
more teeth. This test calculates the absolute offset between one of the camshaft teeth and the crankshaft missing
tooth at idle when that can is at its stop. If the error is greater than the malfunction threshold, a cam/crank
misalignment error will be indicated (P0016 Bank 1, P0018 Bank 2).
For systems that phase the cams immediately off of a cold start for reducing emissions or CSER (Cold Start
Emissions Reduction) the cam position is monitored for functionality during this period of time. There are two ways
to set failures.
Error between the actual position and the expected position is calculated. If the error is greater than a
specified amount, and the Error persists for a period of time, a P052x code is set designating over
advanced or retarded and the bank number. The diagnostic is only executed during CSER phasing.
The diagnostic also checks for a cam position request above a threshold for a period of time, and
determines that the VCT actuator pin is stuck if the cam does not move from the locked position by a
certain amount. This is also only done during CSER operation. If the locking pin is determined to be stuck
then the Oil Control Solenoid (OCS) is cycled on and off for a calibratable amount to allow pressure to
build in the system to unseat the locking pin. If attempts to unstick the locking pin fail, then a P052x code
is set.
The in-use performance ratio numerator for the VCT monitor can be incremented only if the VCT system has been
monitored for both functional and response faults. If the vehicle is operated in a manner that does not ask the VCT
actuators to change position, it may not be possible to evaluate whether they are working properly. As a result, the
in-use ratio numerator checks to see if the commanded VCT position changes sufficiently to detect possible target
errors and with a sufficiently high rate to detect possible slow response. For each drive cycle in which both criteria
are met, the VCT in-use performance numerator will be incremented.
Similar to the previous CCM monitor, the VCT solenoid output driver in the PCM is checked electrically for opens
and shorts (P0010 Bank 1, P0020 Bank 2).
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 109 OF 179
VCT Monitor Operation:
DTCs P0010 - Camshaft Position Actuator Circuit (Bank 1)
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 110 OF 179
Typical VCT monitor malfunction thresholds:
VCT solenoid circuit: Open/short fault set by the PCM driver
Cam/crank misalignment: > or = 7.5 crank degrees
Response/target error - VCT over-advance variance too high: 100 degrees squared
Response/target error - VCT over-retard variance too high: 400 degrees squared
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 111 OF 179
Electronic Throttle Control
The Electronic Throttle Control (ETC) system uses a strategy that delivers engine or output shaft torque, based
on driver demand, utilizing an electronically controlled throttle body. ETC strategy was developed mainly to
improve fuel economy. This is possible by decoupling throttle angle (produces engine torque) from pedal position
(driver demand). This allows the powertrain control strategy to optimize fuel control and transmission shift
schedules while delivering the requested engine or wheel torque.
The Gen2 ETC system was first introduced in 2003MY Ford products. This system evolved into the Gen3 ETC
system in 2008MY and the Gen4 ETC system in 2009MY. The Gen3 and Gen4 ETC systems made
improvements over the Gen2 system by reducing complexity, improving reliability, and optimizing cost. The
primary changes made for the Gen3 / Gen4 ETC systems were the following:
Replace 3-track sensor Accelerator Pedal with 2-track sensor Accelerator Pedal.
Introduce single plunger dual output brake switch.
Integrate the Throttle Plate Position Controller (eTPPC) into the main processor within PCM.
Reduce Quizzer complexity and integrate with the EONV function.
The Gen3 / Gen4 ETC systems have equivalent hardware systems with only software differences.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 112 OF 179
Because safety is a major concern with ETC systems, a complex safety monitor strategy (hardware and
software) was developed. The monitor system is distributed across two processors: the main powertrain control
processor and a monitoring processor called a Quizzer processor.
The primary monitoring function is performed by the Independent Plausibility Check (IPC) software, which resides
on the main processor. It is responsible for determining the driver-demanded torque and comparing it to an
estimate of the actual torque delivered. If the generated torque exceeds driver demand by specified amount, the
IPC takes appropriate mitigating action.
Since the IPC and main controls share the same processor, they are subject to a number of potential, common-
failure modes. Therefore, the Quizzer processor was added to redundantly monitor selected PCM inputs and to
act as an intelligent watchdog and monitor the performance of the IPC and the main processor. If it determines
that the IPC function is impaired in any way, it takes appropriate Failure Mode and Effects Management (FMEM)
actions.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 113 OF 179
ETC System Failure Mode and Effects Management:
No Effect on Drivability A loss of redundancy or loss of a non-critical input could result in a concern that
does not affect driveability. The powertrain malfunction indicator (wrench) and the
malfunction indicator lamp (MIL) do not illuminate, however the speed control may
be disabled. A DTC is set to indicate the component or circuit with the concern.
Delayed APP Sensor This mode is caused by the loss of one APP sensor input due to sensor, wiring, or
Response with Brake PCM concerns. The system is unable to verify the APP sensor input and driver
Override demand. The throttle plate response to the APP sensor input is delayed as the
accelerator pedal is applied. The engine returns to idle RPM whenever the brake
pedal is applied. The powertrain malfunction indicator (wrench) illuminates, but the
MIL does not illuminate in this mode. An APP sensor related DTC is set.
LOS Supercreep Loss of both APP sensor inputs due to sensor, wiring, or PCM concerns, or
internal control mode torque performance, or generator speed or crankshaft
position (CKP) sensor or harness. There is no response when the accelerator
pedal is applied. The engine returns to idle RPM and driver demanded torque
returns to zero whenever the brake pedal is applied. The powertrain malfunction
indicator (wrench) illuminates, but the MIL does not illuminate in this mode. An
internal control module torque performance or internal control module drive
motor/generator/engine speed sensor or APP sensor DTC is set
LOS Supercreep Creep mode is caused by the loss of one brake pedal position (BPP) and one APP
sensor input. The system is unable to determine driver demand. There is no
response when the accelerator pedal is applied. The powertrain malfunction
indicator (wrench) illuminates, but the MIL does not illuminate in this mode. An
APP and BPP sensor, or harness related DTC is set.
RPM Guard with Pedal In this mode, the throttle plate control is disabled due to the loss of both TP sensor
Follower inputs, loss of throttle plate control, stuck throttle plate, significant processor
concerns, or other major electronic throttle body concern. The spring returns the
throttle plate to the default (limp home) position. A maximum allowed RPM is
determined based on the position of the accelerator pedal (RPM Guard). If the
actual RPM exceeds this limit, spark and fuel are used to bring the RPM below the
limit. The powertrain malfunction indicator (wrench) and the MIL illuminate in this
mode and a DTC for an ETC related component is set. EGR and VCT outputs are
set to default values and speed control is disabled.
Shutdown If a significant processor concern is detected, the monitor forces the vehicle to
shutdown by disabling engine, generator and traction motor. The powertrain
malfunction indicator (wrench), MIL, and hazard indicator may illuminate.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 114 OF 179
Transmission Range Sensor Inputs
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Accelerator and Throttle Position Sensor Inputs
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 116 OF 179
Throttle Position Sensor Check Operation:
DTCs P0122, P0123 – TP A circuit continuity (MIL, wrench light)
P0222, P0223 – TP B circuit continuity (MIL, wrench light)
P2135 – TP A / TP B correlation (non-MIL, wrench light)
Monitor execution Continuous
Monitor Sequence None
Sensors OK not applicable
Monitoring Duration < 1 seconds to register a malfunction
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 117 OF 179
Electronic Throttle Monitor
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 118 OF 179
Throttle Plate Position Controller (TPPC) Outputs
The purpose of the TPPC is to control the throttle position to the desired throttle angle. The Gen2 ETC system
has a separate chip embedded in the PCM. The Gen3 / Gen4 ETC systems have the eTPPC function integrated
in the main PCM processor.
For the stand alone TPPC, the desired throttle angle is communicated from the main CPU via a 312.5 Hz duty
cycle signal. The TPPC interprets the duty cycle signal as follows:
6% <= DC < 7% - Commanded default position. Used for key-on, engine off.
8% <= DC < 10% - Closed against hard-stop. Used to learn zero throttle angle position (hard-stop) after
key-up
10% <= DC <=92% - Normal operation, between 0 degrees (hard-stop) and 82%, 10% duty cycle = 0
degrees throttle angle, 92% duty cycle = 82 degrees throttle angle.
92% < DC <= 96% - Wide Open Throttle, 82 to 86 degrees throttle angle.
96% < DC <= 100% - Out of Range, limp home default position
The desired angle is relative to the hard-stop angle. The hard-stop angle is learned during each key-up process
before the main CPU requests the throttle plate to be closed against the hard-stop. The output of the (e)TPPC is
a voltage request to the H-driver (also in PCM). The H driver is capable of positive or negative voltage to the
Electronic Throttle Body Motor.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 119 OF 179
Comprehensive Component Monitor - Engine
Analog inputs such as Intake Air Temperature (P0112, P0113), Cylinder Head Temperature (P1289. P1290),
Mass Air Flow (P0102, P0103) and Throttle Position (P0122, P0123) are checked for opens, shorts, or rationality
by monitoring the analog -to-digital (A/D) input voltage.
The ECT rationality test checks to make sure that ECT is not stuck high in a range that causes other OBD to be
o
disabled. If after a long (6 hour) soak, ECT is very high (> 230 F) and is also much higher than IAT at start, it is
o
assumed that ECT is stuck high. If after a long (6 hour) soak, ECT is stuck midrange between 175 F (typical
o
thermostat monitor threshold temperature) and 230 F and is also much higher than IAT at start, it is assumed that
ECT is stuck mid range.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 120 OF 179
The CHT sensor measures cylinder head metal temperature as opposed to engine coolant temperature. At lower
temperatures, CHT temperature is equivalent to ECT temperature. At higher temperatures, ECT reaches a
maximum temperature (dictated by coolant composition and pressure) whereas CHT continues to indicate cylinder
head metal temperature. If there is a loss of coolant or air in the cooling system, the CHT sensor will still provides
an accurate measure of cylinder head metal temperature. If a vehicle uses a CHT sensor, the PCM software
calculates both CHT and ECT values for use by the PCM control and OBD systems.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 121 OF 179
ECT, IAT, EOT Temperature Sensor Transfer Function
Volts A/D counts in PCM Temperature, degrees F
4.89 1001 -40
4.86 994 -31
4.81 983 -22
4.74 970 -13
4.66 954 -4
4.56 934 5
4.45 910 14
4.30 880 23
4.14 846 32
3.95 807 41
3.73 764 50
3.50 717 59
3.26 666 68
3.00 614 77
2.74 561 86
2.48 508 95
2.23 456 104
1.99 407 113
1.77 361 122
1.56 319 131
1.37 280 140
1.20 246 149
1.05 215 158
0.92 188 167
0.80 165 176
0.70 144 185
0.61 126 194
0.54 110 203
0.47 96 212
0.41 85 221
0.36 74 230
0.32 65 239
0.28 57 248
0.25 51 257
0.22 45 266
0.19 40 275
0.17 35 284
0.15 31 293
0.14 28 302
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 122 OF 179
IAT Rationality Test
The IAT rationality test determines if the IAT sensor is producing an erroneous temperature indication within the
normal range of IAT sensor input.
The IAT sensor rationality test is run only once per power-up. The IAT sensor input is compared to the CHT
sensor input (ECT sensor input on some applications) at key-on after a long (6 hour) soak. If the IAT sensor input
and the CHT (ECT) sensor input agree within a tolerance (+/- 30 deg F), no malfunction is indicated and the test is
complete. If the IAT sensor input and the CHT (ECT) sensor input differ by more than the tolerance, the vehicle
must be driven over maximum electric vehicle speed for 5 minutes to confirm the fault. This is intended to address
noise factors like sun load that can cause the IAT sensor to indicate a much higher temperature than the CHT
(ECT) sensor after a long soak. Driving the vehicle attempts to bring the IAT sensor reading within the test
tolerance. If the IAT sensor input remains outside of the tolerance after the vehicle drive conditions have been
met, the test indicates a malfunction and the test is complete.
In addition to the start-up rationality check, an IAT "Out of Range" check is also performed. The test continuously,
checks to see if IAT is greater than the “IAT Out of Range High threshold”, approximately 150 deg F. In order to
prevent setting false DTC during extreme ambient or vehicle soak conditions, the same count up/count down timer
used for the IAT startup rationality test is used to validate the fault. If IAT is greater than 150 deg F and vehicle
speed is greater than ~ 40 mph for 250 seconds then set a P0111.
Either the IAT startup rationality test or the IAT Out of Range High test can set a P0111 DTC. The logic is designed
so that either fault can trigger a P0111, however, both faults must be OK before the P0111 DTC is cleared.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 123 OF 179
Intake Air Temperature Sensor Out of Range High Check Operation:
DTCs P0111 (Out of Range High)
Monitor execution Continuous
Monitor Sequence None
Sensors OK ECT/CHT, IAT, VSS
Monitoring Duration 250 seconds to register a malfunction
Typical Intake Air Temperature Sensor Out of Range high Entry Conditions
Entry condition Minimum Maximum
Engine off (soak) time 6 hours
Battery Voltage 11.0 Volts
Vehicle speed 35 mph
Time above minimum vehicle speed (if driving req'd) 5 min
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 124 OF 179
Throttle Position Sensor
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 125 OF 179
MAF/TP Rationality Test
The MAF and TP sensors are cross-checked to determine whether the sensor readings are rational and
appropriate for the current operating conditions. (P1A0C)
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 126 OF 179
5 Volt Sensor Reference Voltage Check:
DTCs P0642 (low input), P0643 (high input)
Monitor execution continuous
Monitor Sequence None
Sensors OK not applicable
Monitoring Duration 5 seconds to register a malfunction
Loss of Keep Alive Memory (KAM) power (a separate wire feeding the PCM) results is a P1633 DTC and
immediate MIL illumination on most applications.
Vehicles that require tire/axle information and VIN to be programmed into the PCM Vehicle ID block (VID) will store
a P1639 if the VID block is not programmed or corrupted.
Additional DTCs will be stored to indicate various internal PCM hardware malfunctions:
P0602 - Powertrain Control Module Programming Error indicates that the Vehicle ID block check sum test failed.
P0603 - Powertrain Control Module Keep Alive Memory (KAM) Error indicates the Keep Alive Memory check sum
test failed.
P0604 - Powertrain Control Module Random Access Memory (RAM) Error indicates the Random Access Memory
read/write test failed.
P0605 - Powertrain Control Module Read Only Memory (ROM) Error indicates a Read Only Memory check sum
test failed.
P0607 - Powertrain Control Module Performance indicates incorrect CPU instruction set operation, or excessive
CPU resets.
P068A - ECM/PCM Power Relay De-energized - Too Early. This fault indicates that NVRAM write did not complete
successfully after the ignition key was turned off, prior to PCM shutdown.
P06B8 - Internal Control Module Non-Volatile Random Access Memory (NVRAM) Error indicates Permanent DTC
check sum test failed
The PCM "engine off" or "soak" timer is tested to ensure that it is functional. The value of engine coolant
temperature decays after the engine is turned off. This decay is modeled as a function of ECT, IAT and soak time.
If, during a cold start, (difference between ECT and IAT is low), the actual ECT at start is much lower than the
predicted ECT at start, it means that the soak timer is not functioning and a P2610 DTC is stored. (If the timer fails,
it will read zero seconds and the model will predict that ECT will be the same temperature as when the engine was
last turned off.)
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 127 OF 179
5 Volt Sensor Reference Voltage A Check:
DTCs P0642 (low input)
P0643 (high input)
Monitor execution Continuous
Monitor Sequence None
Sensors OK not applicable
Monitoring Duration 5 sec to register a malfunction
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 128 OF 179
Ignition
New floating point processors no longer use an EDIS chip for ignition signal processing. The crank and cam
position signals are now directly processed by the PCM/ECM microprocessor using a special interface chip called
a Time Processing Unit or TPU. The 36-tooth crankshaft and camshaft position signals come directly into the TPU.
The signals to fire the ignition coil drivers also come from the TPU.
The ignition system is checked by monitoring three ignition signals during normal vehicle operation:
CKP, the signal from the crankshaft 60-2-tooth wheel. The missing teeth are used to locate the cylinder
pair associated with cylinder # 1 The TPU also generates the Profile Ignition Pickup (PIP) signal, a 50%
duty cycle, square wave signal that has a rising edge at 10 deg BTDC.
Camshaft Position (CMP), a signal derived from the camshaft to identify the #1 cylinder
First, several relationships are checked on the 60-2 tooth CKP signal. The TPU looks for the proper number of
teeth (58) after the missing teeth are recognized; time between teeth too low (< 30 rpm or > 9,000 rpm); or the
missing teeth were not where it was expected to be. If an error occurs, the TPU shuts off fuel and the ignition coils
and attempts to resynchronize itself. It takes on revolution to verify the missing tooth, and another revolution to
verify cylinder #1 using the CMP input. Note that if a P0320 DTC is set on a vehicle with Electronic Throttle Control,
(ETC), the ETC software will also set a P2106.
If the proper ratio of CMP events to PIP events is not being maintained (for example, 1 CMP edge for every 8 PIP
edges for an 8-cylinder engine), it indicates a missing or noisy CMP signal (P0340). On applications with Variable
Cam Timing (VCT), the CMP wheel has five teeth to provide the VCT system with more accurate camshaft control.
The TPU checks the CMP signal for an intermittent signal. If an intermittent is detected, the VCT system is
disabled and a P0344 (CMP Intermittent Bank 1) or P0349 (CMP intermittent Bank 2) is set.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 129 OF 179
CKP Ignition System Check Operation:
DTCs P0320 - Ignition Engine Speed Input Circuit
Monitor execution continuous
Monitor Sequence none
Sensors OK
Monitoring Duration < 5 seconds
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 130 OF 179
Coil Primary Ignition System Check Operation:
DTCs P0351 – P0354 (Coil primary)
Monitor execution Continuous
Monitor Sequence None
Sensors OK
Monitoring Duration < 5 seconds
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 131 OF 179
Engine Outputs
The PCM will monitor the "smart" driver fault status bit that indicates either an open circuit, short to power or short
to ground.
The Idle Air Control is functionally checked by monitoring the closed loop idle speed correction required to maintain
the desired idle rpm. If the proper idle rpm cannot be maintained and the system has a high rpm (+100) or low rpm
error (-200) greater than the malfunction threshold, an IAC malfunction is indicated. (P0507, P0506)
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 132 OF 179
Mechanical Returnless Fuel System (MRFS) — Dual Speed
The FP signal is a duty cycle command sent from the PCM to the fuel pump control module. The fuel pump control
module uses the FP command to operate the fuel pump at the speed requested by the PCM or to turn the fuel
pump off. A valid duty cycle to command the fuel pump on, is in the range of 15-47%. The fuel pump control
module doubles the received duty cycle and provides this voltage to the fuel pump as a percent of the battery
voltage. When the ignition is turned on, the fuel pump runs for about 1 second and is requested off by the PCM if
engine rotation is not detected.
The fuel pump control module communicates diagnostic information to the PCM through the FPM circuit. This
information is sent by the fuel pump control module as a duty cycle signal. The 4 duty cycle signals that may be
sent are listed in the following table.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 133 OF 179
MRFS Check Operation:
DTCs P025A – Fuel Pump Control Circuit (opens/shorts)
P025B – Invalid Fuel Pump Control Data (20% duty cycle from FPM)
P0627 – Fuel Pump Secondary Circuit (80% duty cycle from PFM)
U2010B – Fuel Pump Disabled Circuit (40% duty cycle from FPM)
U0109 – Loss of Communication with Fuel Pump Module
Monitor execution once per driving cycle
Monitor Sequence None
Sensors OK
Monitoring Duration 2 seconds
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 134 OF 179
Battery and Battery Charging Systems
The 12V battery is charged by the Direct Current/Direct Current (DC/DC) converter control module. It is enabled
when the high voltage battery contactors have closed, providing high-voltage power to the DC/DC converter
control module.
The Battery Monitoring Sensor continuously monitors the battery state of charge condition and provides the BCM
with this information. The BCM communicates this information to the PCM over the High Speed CAN network (HS-
CAN). The PCM communicates the battery desired set point to the DC/DC converter control module which
supplies the necessary charge voltage to the 12V battery. The Battery Monitoring Sensor also estimates losses in
the battery capacity over time. The Battery Monitoring Sensor should only be reset when the battery is replaced.
The Battery Monitoring Sensor is clamped directly to the negative terminal of the battery and grounds to the vehicle
at the chassis ground connection point through the negative battery cable and eyelet. It is part of the negative
battery cable and cannot be serviced separately.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 135 OF 179
The PCM monitors the low voltage battery for charging performance.
The high voltage battery charging system is responsible for charging the high voltage battery while the vehicle is
not operating. It consists of an Electric Vehicle Supply Equipment (EVSE), Secondary OBD Module (also known as
the Battery Changer Control Module and Charge Port Light Ring (CPLR).
The EVSE is an external AC charger that connects to an external voltage source and the vehicle charge port when
the vehicle is not operating to charge the high voltage battery. The 110V (AC Level 1) charger and cord set plugs
into a standard 110V AC outlet and comes with the vehicle when purchased. The 110V charger is rated up to 12
amps or up to 16 amps depending on the household receptacle being used. It is recommended to use a dedicated
110V electrical outlet to ensure adequate current supply for charging. A 220V (AC Level 2) charging station can
also be utilized which is rated up to 80 amps.
The SOBDM, also known as the Battery Charger Control Module (BCCM), is an air-cooled component that
charges both the high voltage battery and the low voltage (12V) battery when the vehicle is not operating and
plugged into a (110V or 220V) EVSE. The SOBDM is known as the on-board charger. Its primary function is to
coordinate charging operations and convert AC to DC. The SOBDM incorporates an integrated module that
communicates with other modules over the HS-CAN, and is located inside the high voltage battery pack
electronics compartment.
When the EVSE is plugged into the vehicle charging port, the CPLR indicates the current Customer State-of-
Charge (CSoC) and charging operations of the high voltage battery. The CPLR is a light ring surrounding the
charge port inlet that displays charging, charging faults and charging status using four LED light segments.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 136 OF 179
The SOBDM, also known as the BCCM (Battery Charger Control Module), charges the high voltage battery and
has an internal DC to DC Converter Control Module to maintain the 12V battery while vehicle is plugged into an
external 110V or 220V AC EVSE. The SOBDM is an air-cooled component that converts an input voltage of (120
or 240 volts) AC to high-voltage DC and low-voltage DC power, while maintaining electrical isolation between the
systems. When plugged into an external power source the SOBDM is enabled and charges the high voltage
battery (168-361 volts) and the low-voltage battery (12-15 volts). The SOBDM steps the high-voltage down to a
low-voltage (between 12 and 15 volts, depending on vehicle needs), providing power to charge the vehicle low-
voltage battery. During charge the SOBDM incorporates an internal DC/DC converter to charge the low-voltage
battery directly.
When the EVSE cord is plugged in the SOBDM wakes up by sensing a control pilot signal. The pilot signal duty
cycle is analyzed to determine AC line capacity and the frequency is monitored to make sure it is in the proper
range. The EVSE monitors the pilot signal to determine when to turn on AC output. A separate proximity circuit
signal is analyzed to confirm if the connection is stable and the S3 button on the external charger cord is released.
If both signals are in correct range, the SOBDM transmits an on-plug message via HEV HS-CAN. The SOBDM
confirms the gear position is in park and that the vehicle is not in torque producing mode via HEV HS-CAN and
closes an internal S2 switch signaling the EVSE to send AC voltage to the SOBDM. The high voltage system does
not charge if the gear position is is not in park or if the vehicle is started.
Switch S2 detection is determined by the pilot signal voltage change. If the AC voltage input is within range the
SOBDM enables 12V battery charging and wakes up the BECM. While waiting to enter high voltage charging
state, the SOBDM sets low voltage output to a minimum of 12.6V until it receives a low-voltage setpoint from the
PCM via HEV HS-CAN. The SOBDM is ready for high voltage power conversion when it transmits a charger-ready
message via the HEV HS-CAN.
The SOBDM internally transitions from a ready state to charging state of the high voltage battery upon receipt of a
battery charge ready or charging message from the BECM via the HEV HS-CAN. When the BECM status goes
from a charge ready to a charging state the charge contactors are closed to begin charging the high voltage
battery. The SOBDM limits the voltage and current to the high voltage battery based on the maximum voltage and
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 137 OF 179
current requests from the BECM via the HEV HS-CAN. The SOBDM transmits high voltage and current output
internal measurements to the BECM via the HEV HS-CAN.
During high voltage charging the BECM commands the outside air (OSA) duct mode door actuator to open. This
allows outside air to be pulled into the High Voltage Battery pack to cool SOBDM. The BECM monitors the mode
door position and motor circuits and sets a DTC if a fault is detected. The SOBDM monitors its internal temperature
and commands the charger cooling fan speed accordingly to prevent overheating. When high-voltage charging is
complete the BECM charging state HEV HS-CAN message switches from charging to charging complete and
opens the high voltage charge contactors. The SOBDM continues to charge the 12V battery while AC input is
present except when commanded off by the SOBDMC.
During high 12V electrical loads or if the ignition is turned on while the vehicle is plugged in the main DC to DC
Converter Control Module is enabled to charge the 12V battery. If this occurs, the SOBDM disables its low-voltage
support and no longer charges the 12V battery. However, it continues charging the high voltage battery. The
SOBDM shuts down if the PCM no longer requests low-voltage support and the BECM status is charge complete.
If the release button (S3) on the EVSE is pressed while low-voltage or high-voltage charging is in progress, the
SOBDM detects a change of proximity circuit voltage. The high-voltage and the low-voltage DC charging
simultaneously stops. The SOBDM disables power conversion and opens the internal S2 switch. When the EVSE
detects an open S2 switch by sensing a pilot signal voltage change, it drops the AC voltage output to zero so the
charger cord can be safely removed. This prevents arcing of the charge port terminals when the EVSE cord is
disconnected.
The CPLR displays the current CSoC and charging operations of the high voltage battery. When plugged into an
external power source (120 or 240 volts), the CPLR activates the light ring around the charge inlet port and
performs a cord acknowledgment. If successful, this sequence flashes one light segment one at a time in order.
The segments shut off and this sequence repeats 2 times. The CPLR displays charging, charging faults, and
charging status. The light ring is segmented into 4 equal LEDs, each indicating the state of charge: • One segment
flashing < 25% charged • One segment lit (one segment flashing) > 25% charged • Two segments lit (one segment
flashing) > 50% charged • Three segments lit (one segment flashing) > 75% charged. A flashing ring segment
indicates a charge is in progress. When all four rings are solidly lit, the charging operation is complete. If less than
four rings are lit solid charging is not ready. When the charge is complete an internal timer starts to do a 3-5 minute
shutoff to turn the LEDs off and put the module to sleep. The LEDs remain off until a Puddle Light Activation
command is sent via the key fob or door handle. If there is a fault, all LED segments flash rapidly for no more than
5 minutes before going to sleep. LEDs illumination varies depending if it is daytime or nighttime.
To remove the EVSE cord press the release button to stop the charging process. All the LEDs shut off indicating it
is safe to unplug the cord. There is a customer preference setting in the APIM to customize the operation of the
CPLR. The options available include: 1. LEDs On (normal operation) 2. LEDs Off except for Cord
Acknowledgements and Puddle Light Activation requests, 3. LEDs Off (this setting prevents LED operation for any
reason).
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 138 OF 179
Battery Charge Control Module Performance Check Operation:
DTCs P0D24 - Battery Charger Temperature Too High
P0562 - System Voltage Low
P0DAA - Battery Charging System Isolation Fault
Monitor execution Charger active, on-plug, connected to EVSE and charging
Monitor Sequence None
Sensors OK
Monitoring Duration 60 sec
P0D59 - EVSE proximity circuit detected open. Proximity circuit detected >4.8V DC for 5 seconds.
P0D80 – A/C Utility input not present after EVSE S2 switch closed. A/C Input voltage < 85 VAC for 30
seconds.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 139 OF 179
Battery Charge Control Module Performance Check Operation:
DTCs P0D67 - Battery Charger Control Module Performance.
Monitor execution Charger active; connected to EVSE, S2 closed, and utility A/C is
present to charger input
Monitor Sequence None
Sensors OK
Monitoring Duration 60 sec
Internal on-board charger module fault detected that prevents charging functionality. Failure conditions
include:
Low Voltage circuit overvoltage, High Voltage circuit overvoltage, PFC failure, High Voltage circuit
voltage or current control circuit fault, High Voltage circuit current sensor failure.
P0D0F - Negative charge contactor status remains closed. Contactor measurement voltage reported
over CAN to the BECM is >= (pack voltage - 20v) When charge negative contactor is being
commanded from close to open.
P0D09 - Charge positive contactor reported charger voltage over CAN to the BECM is > +/- 5% of
Pack voltage AND the reported charger current over CAN to the BECM is < 0.5 amps AND both
charge contactors are commanded closed AND both charge contactors have power when charge
positive contactor is closed.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 140 OF 179
Battery Charging System Contactor Check Operation:
DTCs P0D0A - Battery Charging System Positive Contactor Control Circuit/Open
P0D0D - Battery Charging System Positive Contactor Control Circuit High
P0D0B - Battery Charging System Positive Contactor Control Circuit
Range/Performance
P0D14 - Battery Charging System Negative Contactor Control Circuit High
Monitor execution
Monitor Sequence None
Sensors OK
Monitoring Duration < 1sec
P0D0A - Charge positive contactor reported charger voltage over CAN to the BECM is > +/- 5% of
Pack voltage AND the reported charger current over CAN to the BECM is < 0.5 amps AND both
charge contactors are commanded closed AND one or both charge contactors DO NOT have power
when charge positive contactor is closed.
P0D0D - Charge positive contactor low side driver in limited current mode.
P0D0B - Charge contactor high side driver in overcurrent mode when any charge contactor is closed.
P0D14 - Charge negative contactor low side driver in limited current mode.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 141 OF 179
High Voltage Battery - Overview
The plug in hybrid can be used as an electric vehicle, conventional hybrid vehicle, or both. The high voltage battery
on the plug in hybrid application has more capacity than a full hybrid application and can be fully charged using
EVSE (Electric Vehicle Supply Equipment) connected to the vehicle charge port. An EV button is located on the
steering wheel to change the vehicle operating strategy.
The vehicle can be placed in electric mode only (EV NOW) allowing only the electric motor to propel the vehicle. In
this mode the high voltage battery depletes and the gas engine does not operate unless a calibratable condition
exists such as a malfunction, heavy acceleration, high electric motor temperature, elevated high voltage battery
temperature, low high voltage battery state of charge, or certain climate control functions are selected (e.g.
defrost).
The high-voltage system utilizes approximately 300 volts DC, provided through high-voltage cables to its
components and modules. The high-voltage cables and wiring are identified by orange harness tape or orange
wire covering. All high-voltage components are marked with high-voltage warning labels with a high-voltage
symbol.
The high voltage battery cell array cover, high voltage battery cell arrays, and high voltage battery wiring harness
are serviced as part of the entire high voltage battery pack.
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 142 OF 179
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 143 OF 179
Battery Energy Control Module Performance Check Operation:
DTCs U0300 - Internal Control Module Software Incompatibility
U019B - Lost Communication With Battery Charger Control Module
U3012 - Control Module Improper Wake-up Performance
B11D5 - Restraints Event - Vehicle Disabled
P0AA6 - Hybrid/EV Battery Voltage System Isolation Fault
Monitor execution
Monitor Sequence None
Sensors OK
Monitoring Duration < 1 sec
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 144 OF 179
Battery Pack Sensor Check Operation:
DTCs P0AA7 - Hybrid/EV Battery Voltage Isolation Sensor Circuit
P1A3A - Hybrid/EV Battery Pack Voltage Sense System - Multiple Sensor Correlation
P1A39 - Hybrid/EV Battery Temperature Sensor System - Multiple Sensor Correlation
Monitor execution
Monitor Sequence None
Sensors OK
Monitoring Duration < 1 sec
P0AA7 - The estimated pack voltage derived from the sum of the positive and negative leakage voltage is
not <= 22.3982 v of the actual measured pack voltage
P1A3A - Pack voltage > 390 V, or < 1/2 of sum of cell voltages, and Half pack voltage < 35 V, or > 200V
P1A39 - 3 or more temperature sensor faults (there are 10 sensors total) > 95 deg C, or < -50 deg C, or
| Any temp sensor - average of all temp sensors | > 25 deg C."
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 145 OF 179
Battery Pack Performance Check Operation:
DTCs P0B24 - Hybrid/EV Battery ""A"" Voltage Unstable
P0C30 - Hybrid/EV Battery Pack State of Charge High
P0AFB - Hybrid/EV Battery System Voltage High
P0B25 - Hybrid/EV Battery "A" Voltage Low
P0D37 - Hybrid/EV Battery System Current High
P0A7F - Hybrid/EV Battery Pack Deterioration
Monitor execution
Monitor Sequence None
Sensors OK
Monitoring Duration < 15 seconds
P0B24 - Average cell voltage minus any cell voltage > 0.5 volts for 15 sec
P0C30 -
State of charge => 100% when charge contactors are open (main contactors open or closed)
Cell voltage > 4.5V when charge contactors are open (main contactors open or closed)
State for charge => 101% when charge contactors are closed
Cell voltage > 4.14 V when charge contactors are closed
P0AFB – Pack voltage > 362 V
P0B25 – State of change = 0% with main contactors open or closed
P0D37 – Battery current > 180 A for 200 sec, or > 250 A for 60 sec.
P0A7F – Battery pack power < 12 KW
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 146 OF 179
Battery Pack Cell Balance Circuit Check Operation:
DTCs P0DAD - Hybrid/EV Battery Cell Balancing Circuit "A" Stuck On.
P0DB1 - Hybrid/EV Battery Cell Balancing Circuit "B" Stuck On.
P0DB5 - Hybrid/EV Battery Cell Balancing Circuit "C" Stuck On.
P0DB9 - Hybrid/EV Battery Cell Balancing Circuit "D" Stuck On.
P0DBD - Hybrid/EV Battery Cell Balancing Circuit "E" Stuck On.
P0DC1 - Hybrid/EV Battery Cell Balancing Circuit "F" Stuck On.
P0DC5 - Hybrid/EV Battery Cell Balancing Circuit "G" Stuck On.
P0DC9 - Hybrid/EV Battery Cell Balancing Circuit "H" Stuck On.
P0DCD - Hybrid/EV Battery Cell Balancing Circuit "I" Stuck On.
P0DD1 - Hybrid/EV Battery Cell Balancing Circuit "J" Stuck On.
P0DD5 - Hybrid/EV Battery Cell Balancing Circuit "K" Stuck On.
P0DD9 - Hybrid/EV Battery Cell Balancing Circuit "L" Stuck On.
P0DDD - Hybrid/EV Battery Cell Balancing Circuit "M" Stuck On.
P0DE1 - Hybrid/EV Battery Cell Balancing Circuit "N" Stuck On.
P0DAE - Hybrid/EV Battery Cell Balancing Circuit "A" Stuck Off.
P0DB2 - Hybrid/EV Battery Cell Balancing Circuit "B" Stuck Off.
P0DB6 - Hybrid/EV Battery Cell Balancing Circuit "C" Stuck Off.
P0DBA. Hybrid/EV Battery Cell Balancing Circuit "D" Stuck Off.
P0DBE. Hybrid/EV Battery Cell Balancing Circuit "E" Stuck Off.
P0DC2 - Hybrid/EV Battery Cell Balancing Circuit "F" Stuck Off.
P0DC6 - Hybrid/EV Battery Cell Balancing Circuit "G" Stuck Off.
P0DCA - Hybrid/EV Battery Cell Balancing Circuit "H" Stuck Off.
P0DCE. Hybrid/EV Battery Cell Balancing Circuit "I" Stuck Off.
P0DD2 - Hybrid/EV Battery Cell Balancing Circuit "J" Stuck Off.
P0DD6 - Hybrid/EV Battery Cell Balancing Circuit "K" Stuck Off.
P0DDA - Hybrid/EV Battery Cell Balancing Circuit "L" Stuck Off.
P0DDE - Hybrid/EV Battery Cell Balancing Circuit "M" Stuck Off.
P0DE2 - Hybrid/EV Battery Cell Balancing Circuit "N" Stuck Off.
Monitor execution At a power up before contactors are closed, and two consecutive
power cycles
Monitor Sequence None
Sensors OK
Monitoring Duration 100 msec
For the 6 cells monitored by each circuit: Any individual cell voltage differs from the average cell voltage by >
75 mV
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 147 OF 179
Battery Pack Contactor Check Operation:
DTCs P0AA4 - Hybrid/EV Battery Negative Contactor Circuit Stuck Closed
P0AA5 - Hybrid/EV Battery Negative Contactor Circuit Stuck Open
P0AA2 - Hybrid/EV Battery Positive Contactor Circuit Stuck Open
P0B37 - High Voltage Service Disconnect Open
Monitor execution
Monitor Sequence None
Sensors OK
Monitoring Duration < 1 sec
FORD MOTOR COMPANY REVISION DATE: APRIL 5, 2013 PAGE 148 OF 179
Battery Pack Contactor Check Operation:
DTCs P0ADD - Hybrid/EV Battery Negative Contactor Control Circuit/Open
P0AE0 - Hybrid/EV Battery Negative Contactor Control Circuit High
P0AD9 - Hybrid/EV Battery Positive Contactor Control Circuit/Open
P0ADC - Hybrid/EV Battery Positive Contactor Control Circuit High
P0ADA - Hybrid/EV Battery Positive Contactor Control Circuit Range/Performance.
Monitor execution
Monitor Sequence None
Sensors OK
Monitoring Duration < 1 sec
P0ADD - battery interlock is normal AND PSR or Charge Wakeup is High AND Negative Contactor state is
open AND one of the following is TRUE when negative contactor is closed:
1.) completed the power up sequence and contactors are commanded closed but no power
2.) pre-charge is NOT yet complete and contactors are commanded closed but no power.
P0AE0 - Negative contactor low side driver in limited current mode.
P0AD9 - battery interlock is normal AND PSR or Charge Wakeup is High AND Positive Contactor state is
open AND one of the following is TRUE when positive contactor is closed:
1.) completed the power up sequence and contactors are commanded closed but no power
2.) pre-charge is NOT yet complete and contactors are commanded closed but no power.
P0ADC - Positive contactor low side driver in limited current mode.
P0ADA – Positive contactor high side driver in over current mode.
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Battery Pack Precharge Contactor Check Operation:
DTCs P0AE1 - Hybrid/EV Battery Precharge Contactor Circuit
P0AE7 - Hybrid/EV Battery Precharge Contactor Control Circuit High
P0AE5 - Hybrid/EV Battery Precharge Contactor Control Circuit
Range/Performance
Monitor execution
Monitor Sequence None
Sensors OK
Monitoring Duration < 1 sec
P0AE1 - Battery current < -10A or > -10A when precharge contactor is commanded closed
P0AE7 - Precharge contactor lowside driver in limited current mode
P0AE5 - | Pack voltage - sum of contactor voltages | > 20V when precharge contactor is commanded
closed.
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Powersplit Transaxle
Transmission Inputs
A Rotor position sensor (resolver) is located on both the electric Motor and Generator and is used to detect the
angular position of the rotor. The analog waveform generated by the resolver is converted into a digital signal by
the Resolver to Digital (R/D) converter. The digital signal is used to calculate speed and angular acceleration which
is used to control the electric Motor and Generator. The speed information is also used to calculate vehicle speed
and is broadcasted to other modules over CAN. If a resolver hardware or wiring fault is detected, or a failure with
the R/D converter is detected, a P0A90-xx fault for the motor or a P0A92-xx fault for the generator will be stored. If
the resolver was not properly configured (initialized) by the assembly plant or if the ISC is replaced, a P0A3F-55
will be stored for the motor, or P0A4B-55 will be stored for the generator.
Temperature Sensors
The Transmission Fluid Temperature Sensor (TFT) is monitored for open and short circuit faults and for in-range
faults (P0710-xx) where Trans Fluid, Motor Coil and Generator Coil temperatures do not correlate properly.
The Motor and Generator Coil Temperature Sensors are monitored for open and short circuit faults and for in-
range faults where Trans Fluid, Motor Coil and Generator Coil temperatures do not correlate properly. P0A2A-xx
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and P0A2B-xx are related to Motor Coil Sensor failure, P0A36-xx and P0A37-xx are related to Generator Coil
Sensor failure. The Motor and Generator coils are also monitored for over-temperature (P0A2F-94).
The Motor and Generator Inverter Temperature Sensors are monitored for open and short circuit faults. P0A78-11
and P0A78-13 are related to Motor Inverter Sensor failure, P0A7A-11 and P0A78-13 are related to Generator
Inverter Sensor failure. The Motor and Generator Inverters are also monitored for over-temperature (P0A3C-94).
HPCM Outputs
Inverter Control
Upon receiving the wheel torque demanded by the driver from the ECM over CAN communication, the HPCM
calculates the required torque of the electric Motor and Generator to meet driver demand. The HPCM will then
control the inverter over U, V, and W phase gate signals to regulate DC current into AC current that is fed into the
stator.
The Motor and Generator gate signal lines are monitored for open circuits. A P0A78-1C and P0A78-11 faults are
for the Motor and a P0A7A-1C and P0A78-11 are for the Generator. The inverter is also monitored for various
faults such as over current, current sensor fault, current regulation fault, temperature sensor fault, etc. and will store
a P0A78 fault for the Motor and a P0A7A fault for the Generator upon detection of a malfunction.
The HPCM monitors itself by using various software monitoring functions. The flash ROM is checked using a
checksum calculation, and will set P0605-00 if ROM errors are detected. The EEPROM is emulated in the flash
ROM.
The Motor/Generator Control Unit (MGCU) use similar types of RAM/ROM tests. If a fault is detected, a the MGCU
will request to store P0A1B-06, P0A1B-49, P060C-41, or P060C-43 and these will be reported by the HPCM.
The HPCM receives information from the ECM (and various other modules) via CAN. If the CAN link fails, the
HPCM no longer has torque or engine speed information available. The HPCM will store a U0100-00 fault code if it
doesn’t receive any more CAN messages from the ECM.
The HPCM receives wheel speed and brake torque request information from the Antilock Brake System (ABS)
module. The HPCM will store U0121-00 fault code if communication with the ABS module is lost. The HPCM also
receives information from the Battery Energy Control Module (BECM) and a U0111-00 fault will be stored if the
communication with the BECM is lost.
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Hybrid Powertrain Control Module
The HPCM monitors several hardwired inputs from the following sources:
High Voltage (HV) Interlock (HVIL) is a switched input that monitors access to the HV DC connectors. If
opened, it will cause the HV circuit to be de-energized and the vehicle will be shut down.
Clean Tach Out (CTO) is a signal from the ECM, which is used to determine Engine Speed.
Electric Motor Position Sensors are used to measure the angular position of the rotor for the motor and
generator.
Electric Drive Temperature Sensors are used to monitor hardware component temperatures that are
critical to the electric drive system.
Electric Vehicle (EV) Mode is a driver-selectable switched input that determines the driver’s request for
one of the special EV driving modes (PHEV only).
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CTO (Clean Tach Out)
The CTO signal is sent from the ECM to the HPCM. The signal is sent at 10 degrees before Top Dead Center
(TDC) for each cylinder. Thus, for a 4 cylinder engine, this translates into the HPCM seeing this signal every 180
degrees of engine rotation. This signal is used to calculate Engine Speed and engine rotational position.
CTO Input Circuit Failure and Out- of- Range check entry conditions:
Entry Conditions Minimum Maximum
Time after vehicle power up 500 msec none
12V Battery voltage 6.0 V 19.0 V
Engine Speed 50 rad/s 200 rad/s
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Electric Motor Position Sensors
These are used to measure the angular position of the rotor for the motor and generator. They are used by low-
level machine control algorithms to calculate current angle. Also, they are used by higher-level control strategies to
determine motor and generator rotational speeds and accelerations.
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Internal Communication Fault Check PASS
Internal Reference Voltages Fault Check PASS
Gate Drive Circuit Fault Check PASS
Motor/Gen Performance
35A difference between command and feedback for 500ms continuously.
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Electric Motor HV Current Sensors
These are used by the MGCU (Motor/Generator Control Unit) to measure the AC current for each phase of the
motor and generator. They are used by low-level machine control algorithms to calculate current magnitude and
angle. Also, they are used by to insure correct connection of the AC 3-phase circuits to the motor and generator.
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Motor/Gen Inverter Performance Current Above Threshold malfunction thresholds:
Motor/Gen current sensor over current declared by MGCU:
Motor current magnitude > 600A for 400us OR > 30 A for 200ms at power up
Generator current magnitude > 300A for 400us OR > 15 A for 200ms at powerup
Variable Voltage Controller Control Circuit Current Above Threshold malfunction thresholds:
Variable Voltage Controller current measured greater than 300 amps.
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Electric Drive Temperature Inputs
Motor/Generator Coil Temperature Sensors
These temperature sensors are located on the coil windings of the stators of the motor and the generator.
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Motor/Generator Coil Temp In-Range/Performance entry conditions:
Entry Conditions Minimum Maximum
Time after vehicle power up 2 seconds 10 seconds
12V Battery voltage 6.0V 19.0 V
Sensors OK Motor Temp Sensor = OK
Generator Temp Sensor = OK
Oil Temp Sensor = OK
Internal Reference Voltages Fault Check PASS
Key-off timer 200 minutes
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Transmission Fluid (Oil) Temperature Sensor
The Transmission Fluid Temperature sensor measures the temperature of the transmission fluid.
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Motor/Generator Inverter Temperature Sensors
These temperature sensors are located on the Motor and Generator Inverters.
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High Voltage DC/DC Converter
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Inverter DC/DC Converter Check Operation:
DTCs P1A16 - Variable Voltage Controller Voltage Control Circuit
P1A17 - Variable Voltage Controller Processor
P0A94 - DC/DC Converter Performance
Monitor execution Continuous
Monitor Sequence None
Sensors OK P0560, P0562, U0111, P1A07
Monitoring Duration Continuous
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Inverter Inductor Temperature Sensor Check Operation:
DTCs P1A18 - Variable Voltage Controller Inductor Temperature Sensor Circuit
P1A19 - Variable Voltage Controller Driver Temperature Sensor Circuit
Monitor execution Continuous
Monitor Sequence None
Sensors OK P0560, P2610
Monitoring Duration Continuous
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EV Mode Input Switch (PHEV only)
Electric Vehicle (EV) Mode is driver-selectable switched input that determines the driver’s request for one of the
three EV driving modes: Auto – this is normal PHEV operation (charge depleting) which attempts to minimize use
of internal combustion engine operation until PHEV battery is mostly depleted then reverts to conventional hybrid
(charge sustaining) operation, EV Now – this mode forces the internal combustion engine off under all non-faulted
driving conditions, and EV Later – this mode forces the vehicle into conventional hybrid (charge sustaining) to
allow a reserve of battery energy to be used later once driver selects Auto mode again.
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Transmission Range Sensor Inputs
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Transmission Auxiliary Oil Pump
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Motor Electronics Coolant Pump Control Circuit
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General System Voltage Checks
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Internal ECU Checks
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General Hybrid System
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PCM On Board Diagnostic Executive
The On-Board Diagnostic (OBD) Executive is a portion of the PCM strategy that manages the diagnostic
trouble codes and operating modes for all diagnostic tests. It is the "traffic cop" of the diagnostic system. The
Diagnostic Executive performs the following functions:
Sequence the OBD monitors such that when a test runs, each input that it relies upon has already
been tested. For 2008 MY and beyond ISO 14229 programs, the OBD monitors are no longer
sequenced by the diagnostic executive.
Controls and co-ordinates the execution of the individual OBD system monitors: Catalyst, Misfire,
EGR, O2, Fuel, AIR, EVAP and, Comprehensive Component Monitor (CCM). For 2008 MY and
beyond ISO 14229 programs, the execution of the OBD monitors is no longer controlled and
coordinated by the diagnostic executive.
Stores freeze frame and "similar condition" data.
Manages storage and erasure of Diagnostic Trouble Codes as well as MIL illumination.
Controls and co-ordinates the execution of the On-Demand tests: Key On Engine Off (KOEO)Key
On Engine Running (KOER), and the Output Test Mode (OTM). For 2008 MY and beyond ISO
14229 programs, the Output Test Mode is no longer supported by the diagnostic executive.
Performs transitions between various states of the diagnostic and powertrain control system to
minimize the effects on vehicle operation.
Interfaces with the diagnostic test tools to provide diagnostic information (I/M readiness, various J1979 test
modes) and responses to special diagnostic requests (J1979 Mode 08 and 09).
Tracks and manages indication of the driving cycle which includes the time between two key on events
that include an engine start and key off.
The diagnostic executive also controls several overall, global OBD entry conditions.
The battery voltage must fall between 11.0 and 18.0 volts to initiate monitoring cycles.
The engine must be started to initiate the engine started, engine running, and engine off monitoring cycles.
The Diagnostic Executive suspends OBD monitoring when battery voltage falls below 11.0 volts.
The Diagnostic Executive suspends monitoring of fuel-system related monitors (catalyst, misfire, evap,
O2, AIR and fuel system) when fuel level falls below 15%. For 2005 MY and beyond, the execution of
the fuel related OBD monitors is no longer suspended for fuel level by the diagnostic executive.
The diagnostic executive controls the setting and clearing of pending and confirmed DTCs.
A pending DTC and freeze frame data is stored after a fault is confirmed on the first monitoring cycle. If the
fault recurs on the next driving cycle, a confirmed DTC is stored, freeze frame data is updated, and the
MIL is illuminated. If confirmed fault free on the next driving cycle, the pending DTC and freeze frame data
is erased on the next power-up.
For the 2005 MY and later, pending DTCs will be displayed as long as the fault is present. Note that OBD-
II regulations required a complete fault-free monitoring cycle to occur before erasing a pending DTC. In
practice, this means that a pending DTC is erased on the next power-up after a fault-free monitoring cycle.
For clearing comprehensive component monitoring (CCM) pending DTCs, the specific monitor must
determine that no fault is present, and a 2-hour engine off soak has occurred prior to starting the vehicle.
The 2-hour soak criteria for clearing CCM confirmed and pending DTCs has been utilized since the 2000
MY. For 2008 MY and beyond ISO 14229 programs, the engine off soak is no longer used by the
diagnostic executive.
After a confirmed DTC is stored and the MIL has been illuminated, three consecutive confirmed fault-free
monitoring cycles must occur before the MIL can be extinguished on the next (fourth) power-up. After 40
engine warm-ups, the DTC and freeze frame data is erased.
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The diagnostic executive controls the setting and clearing of permanent DTCs.
A permanent DTC is stored when a confirmed DTC is stored, the MIL has been illuminated, and there are
not yet six permanent DTCs stored.
After a permanent DTC is stored, three consecutive confirmed fault-free monitoring cycles must occur
before the permanent DTC can be erased.
After a permanent DTC is stored, one confirmed fault-free monitoring cycle must occur, following a DTC
reset request, before the permanent DTC can be erased. For 2010MY and beyond ISO 14229 programs
a driving cycle including the following criteria must also occur, following the DTC reset request, before a
permanent DTC can be erased:
o Cumulative time since engine start is greater than or equal to 600 seconds;
o Cumulative vehicle operation at or above 25 miles per hour occurs for greater than or equal
to 300 seconds (medium-duty vehicles with diesel engines certified on an engine
dynamometer may use cumulative operation at or above 15% calculated load in lieu of at or
above 25 miles per hour for purposes of this criteria); and
o Continuous vehicle operation at idle (i.e., accelerator pedal released by driver and vehicle speed
less than or equal to one mile per hour) for greater than or equal to 30 seconds.
A permanent DTC can not be erased by a KAM clear (battery disconnect). Additionally, its confirmed DTC
counterpart will be restored after completion of the KAM reset (battery reconnect).
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Exponentially Weighted Moving Average
Exponentially Weighted Moving Averaging is a well-documented statistical data processing technique that is used
to reduce the variability on an incoming stream of data. Use of EWMA does not affect the mean of the data,
however, it does affect the distribution of the data. Use of EWMA serves to “filter out” data points that exhibit
excessive and unusual variability and could otherwise erroneously light the MIL.
New Average = [New data point * “filter constant”] + [( 1 - “filter constant” ) * Old Average]
This equation produces an exponential response to a step-change in the input data. The "Filter Constant"
determines the time constant of the response. A large filter constant (i.e. 0.90 ) means that 90% of the new data
point is averaged in with 10% of the old average. This produces a very fast response to a step change.
Conversely, a small filter constant (i.e. 0.10 ) means that only 10% of the new data point is averaged in with 90%
of the old average. This produces a slower response to a step change.
When EWMA is applied to a monitor, the new data point is the result from the latest monitor evaluation. A new
average is calculated each time the monitor is evaluated and stored in Keep Alive Memory (KAM). This normally
occurs each driving cycle. The MIL is illuminated and a DTC is stored based on the New Average store in KAM.
In order to facilitate repair verification and DDV demonstration, 2 different filter constants are used. A “fast filter
constant” is used after KAM is cleared or DTCs are erased and a “normal filter constant” is used for normal
customer driving. The “fast filter” is used for 2 driving cycles after KAM is cleared/DTCs are erased, and then the
“normal filter” is used. The “fast filter” allows for easy repair verification and monitor demonstration in 2 driving
cycles, while the normal filter is used to allow up to 6 driving cycles, on average, to properly identify a malfunction
and illuminate the MIL. This feature is called Fast Initial Response (FIR). The fast filter is always calibrated to 1.0
which means that the EWMA is effectively disabled because the new average is 100% of the new data point.
Since the EWMA is effectively disabled, it takes twp driving cycles to set the MIL. The first driving cycle with a
fault will set a pending DTC; the second driving cycle will set a confirmed code and illuminate the MIL.
The other unique feature used with EWMA is called Step Change Logic (SCL). This logic detects an abrupt
change from a no-fault condition to a fault condition. This is done by comparing the new data point to the EWMA
old average. If the two points differ by more than a calibrated amount (i.e. the new data point is outside the
normal distribution), it means that a catastrophic failure has occurred. The fast filter is then used in the same
manner as for the FIR feature above. Since the EWMA is effectively disabled, it takes twp driving cycles to set the
MIL. The first driving cycle with a fault will set a pending DTC; the second driving cycle will set a confirmed code
and illuminate the MIL. The SCL becomes active after the 4th "normal" monitoring cycle to give the EWMA a
chance to stabilize.
During "normal" EWMA operation, a slower filter constant is used. The "normal filer" allows the MIL to be
illuminated in 1 to 6 driving cycles. A confirmed code is set and the MIL is illuminated as soon as the EWMA
crosses the malfunction threshold. There is no pending DTC because EWMA uses a 1-trip MIL.
In order to relate filter constants to driving cycles for MIL illumination, filter constants must be converted to time
constants. The mathematical relationship is described below:
The evaluation period is a driving cycle. The time constant is the time it takes to achieve 68% of a step-change to
an input. Two time constants achieve 95% of a step change input.
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EWMA Examples
EWMA with FIR and SCL has been incorporated in the catalyst monitor, the Rear O2 response test and the EONV
Evaporative system leak check monitor. There are 3 calibrateable parameters that determine the MIL illumination
characteristics.
“Fast” filter constant (0.9999), used for 2 driving cycles after DTCs are cleared/KAM is reset (FIR) and for Step
Change Logic (SCL)
“Normal” filter constant( typically 0.4),, used for all subsequent, “normal” customer driving
Number of driving cycles to use fast filter after KAM clear (normally set to 2 driving cycles)
Several examples for a typical catalyst monitor calibration are shown in the tables below. The first example does
not show SCL in order to better illustrate the EWMA calculation and the 1-trip MIL.
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I/M Readiness Code
The readiness function is implemented based on the J1979 format. A battery disconnection or clearing codes
using a scan tool results in the various I/M readiness bits being set to a “not-ready” condition. As each non-
continuous monitor completes a full diagnostic check, the I/M readiness bit associated with that monitor is set to a
“ready” condition. This may take one or two driving cycles based on whether malfunctions are detected or not.
The readiness bits for comprehensive component monitoring, misfire and fuel system monitoring are considered
complete once all the non-continuous monitors have been evaluated. Because the evaporative system monitor
o
requires ambient conditions between 40 and 100 F and BARO > 22.5 " Hg (< 8,000 ft.) to run, special logic can
“bypass” the running the evap monitor for purposes of clearing the evap system I/M readiness bit due to the
continued presence of these extreme conditions.
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Catalyst Temperature Model
A catalyst temperature model is currently used for entry into the catalyst and oxygen sensor monitors. The
catalyst temperature model uses various PCM parameters to infer exhaust/catalyst temperature. For the 1998
MY, the catalyst temperature model has been enhanced and incorporated into the Type A misfire monitoring
logic. The model has been enhanced to include a misfire-induced exotherm prediction. This allows the model to
predict catalyst temperature in the presence of misfire.
The catalyst damage misfire logic (Type A) for MIL illumination has been modified to require that both the catalyst
damage misfire rate and the catalyst damage temperature is being exceeded prior to MIL illumination. This
change is intended to prevent the detection of unserviceable, unrepeatable, burst misfire during cold engine start-
up while ensuring that the MIL is properly illuminated for misfires that truly damage the catalyst.
Beginning with the 2007 MY, the catalyst temperature model is also used to generate the primary inputs to the
CSER Monitor as described in that section of this document.
The instrument cluster on some vehicles uses the CAN data link to receive and display various types of
information from the PCM. For example, the engine coolant temperature information displayed on the instrument
cluster comes from the same ECT sensor used by the PCM for all its internal calculations.
These same vehicles use the CAN data link to illuminate the MIL rather than a circuit, hard-wired to the PCM.
The PCM periodically sends the instrument cluster a message that tells it to turn on the MIL, turn off the MIL or
blink the MIL. If the instrument cluster fails to receive a message within a 5-second timeout period, the instrument
cluster itself illuminates the MIL. If communication is restored, the instrument cluster turns off the MIL after 5
seconds. Due to its limited capabilities, the instrument cluster does not generate or store Diagnostic Trouble
Codes.
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