6.7L Diesel
6.7L Diesel
of technical advancements in the 6.7L POWER STROKE® DIESEL Engine. The information
contained in this publication will supplement information contained in available service
information.
                                              1
2
                                                    6.7L POWER STROKE® DIESEL
TABLE OF CONTENTS
COMPONENT LOCATION.............................................................................................. 9
UPPER ENGINE COMPONENTS................................................................................. 15
LOWER ENGINE COMPONENTS................................................................................ 17
COOLING SYSTEM...................................................................................................... 23
Primary Cooling System.....................................................................................................................................................24
Powertrain Secondary Cooling System............................................................................................................................27
LUBRICATION SYSTEM.............................................................................................. 33
Lubrication System Oil Flow..............................................................................................................................................33
FUEL SYSTEM............................................................................................................. 51
Fuel Supply System............................................................................................................................................................52
Fuel Management System..................................................................................................................................................56
ELECTRICAL COMPONENTS..................................................................................... 63
Pressure Sensors................................................................................................................................................................64
Position Sensors.................................................................................................................................................................70
Miscellaneous Sensors.......................................................................................................................................................71
Outputs.................................................................................................................................................................................72
EXHAUST SYSTEM...................................................................................................... 77
Regeneration Process........................................................................................................................................................81
Selective Catalyst Reduction (SCR) System Operation..................................................................................................86
                                                                                           3
4
Direct Injection
Turbocharged
Diesel Engine
       5
                                               6.7L POWER STROKE® DIESEL OVERVIEW
Engine Features
•	 The 6.7L Power Stroke® diesel has been designed to meet the tougher emissions standards set by the government.
•	 The 6.7L Power Stroke® diesel has been designed to meet the customer’s expectations of high horsepower and torque
   over a wide RPM range.
•	 Meeting the more stringent customer and regulatory demands are accomplished in part by a high pressure common rail
   fuel system, DualBoost turbocharger system, 4 valves per cylinder, and a Selective Catalyst Reduction (SCR) system.
                            650
                                                                                                                                   350
                            600
                            550
                                                                                                                                   300
                            500
           Torque (lb-ft)
                                                                                                                                             Power (BHP)
                            450                                                                                                    250
                            400
                            350                                                                                                    200
                            300
                                                                                                                                   150
                            250
                            200
                                                                                                                                   100
                            150                                                                         2011 6.7L Torque
                            100                                                                         735
                                                                                                                                   50
                                   50                                                                   2011 6.7L HP
                                                                                                        390
                                   0                                                                                           0
                                    600        800    1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800
                                                                             Engine Speed (RPM)
                                   750                                                                                         350
                                   700
                                   650                                                                                         300
                                   600
                                   550
                                                                                                                               250
                                   500
                                   450
                  Torque (lb-ft)
Power (BHP)
                                                                                                                               200
                                   400
                                   350
                                                                                                                               150
                                   300
                                   250
                                                                                                                               100
                                   200
                                   150
                                   100                                                              2011 6.7L Torque           50
                                                                                                    660
                                    50                                                              2011 6.7L HP
                                                                                                    300
                                        0                                                                                      0
                                         600    800    1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600
                                                                             Engine Speed (RPM)
                                                                                     6
                                          OVERVIEW
                           6.7L Power Stroke® Diesel Specifications
6 2
7 3
8 4
                                               7
NOTES
  8
            COMPONENT LOCATION
                                     Front of Engine
                                     1.	 Air Inlet from air filter
1                        6           2.	 Exhaust Gas Recirculation (EGR)
                                         cooler outlet temperature sensor
                                     3.	 Front Engine Accessory Drive
                                         (FEAD) idler pulley
                                     4.	 Camshaft Position (CMP) sensor
                                     5.	 Primary coolant pump
                                     6.	 Air inlet from Charge Air Cooler
                                         (CAC)
2 5
                    9
                                      COMPONENT LOCATIONS
Left of Engine
1.	 Oil level indicator
                                                 1
2.	 Fuel Rail Pressure (FRP) sensor
3.	 Engine oil cooler
4.	 Fuel return line
                                         2
                                                                3
                                                     10
        COMPONENT LOCATIONS
                                 Rear of Engine
                                 1.	 Turbocharger Exhaust Supply
                                 2.	 Spin-on oil filter
                                 3.	 Turbo Outlet Pipe (Cobra Head)
                11
                                    COMPONENT LOCATIONS
Right Side of Engine
1.	 EGR cooler                                                4
2.	 Oil pressure switch
3.	 Engine Oil Temperature (EOT)
    sensor                             1
4.	 Engine Coolant Temperature 2
    (ECT2) sensor
                                               12
            COMPONENT LOCATIONS
                                              Left Top of Engine
                                              1.	 Engine Coolant Temperature
                                                  (ECT) sensor
                                              2.	 Wastegate control vacuum
                              9                   solenoid
                                              3.	 Fuel Rail Temperature (FRT)
                                              4.	 Fuel Pressure Switch (FPS)
                                              5.	 Engine mounted fuel filter
                                              6.	 Fuel supply line
                                              7.	 Injector Quantity Adjustment (IQA)
1                                                 sticker
                                              8.	 Turbocharger compressor outlet
                                              9.	 Manifold Absolute Pressure (MAP)
                                                  sensor
                                          8
    3
                                      7
        4            6
            5
    2
                                  5
                     4
                 3
                         13
NOTES
  14
                             UPPER ENGINE COMPONENTS
Intake Valves
                                    6
                                5
                     4
Exhaust Outlet
Coolant Outlet
                                                                Rocker Arms
                                           Rocker Arm for       Each valve has its own rocker arm and
                                             each Valve         push rod.
                                                                Note: The rocker arms are not
                                                                attached by head bolts.
                                             15
                                  UPPER ENGINE COMPONENTS
Rocker Arms continued
The rocker arms for each cylinder ride
on their own common fulcrum. They
are attached to the cylinder heads by
two bolts.
Note: individual rocker arms reduce
side loading of the valves.
Cam Followers
•	 Patented design (Ford).
•	 Each roller lifter contains two
   hydraulic lash adjusters and each
   valve is individually actuated
   through its own pushrod & rocker
   arm
•	 Simple stamped rocker arms allow
   efficient package, robust quality, &
   reliable motion
•	 Eliminates the floating bridge used
   to open a pair of valves with a
   single rocker arm, improving wear
   performance and NVH.
Oiling Manifold
                                             16
                                 LOWER ENGINE COMPONENTS
1 2 3 4 5 6
Engine Block
•	 The engine block is made from a compacted graphite iron (CGI) enables best-in-class weight and improved Noise,
   Vibration, and Harshness (NVH).
•	 Cam-in-block design with dry valley
•	 Integrated Direct Mount for High Pressure Fuel Pump.
•	 Six head bolts are used per cylinder and six bolts per main bearing cap.
                                                            17
                                   LOWER ENGINE COMPONENTS
Crankshaft
The following improvements have
been made to the crankshaft.
•	 Improved crank quality.
•	 Fillet radius on each journal
•	 Forged Modular Steel
•	 Undercut rolled fillet radius
•	 Fully lightened crankshaft pins
•	 Two radiused counterweights
•	 One piece rear flange:
   –– increase torque capabilities.
   –– improved sealing and balance.
•	 Shrink fit assembled front drive gear
•	 Single mode torsional damper
•	 Direct accessory drive for improved
   NVH
Pistons
The pistons are oil cooled. A oil jet that
bolts into the block sprays oil into a
hole in the bottom of the piston. The                        Oil Enters
oil flows through the top of the piston
and exits from a hole in the other side
of the piston.
Oil Exits
Connecting Rods
The connecting rod is a fractured cap
design.
                                              18
                   LOWER ENGINE COMPONENTS
                                       Camshaft
                                       The camshaft is driven by the
                                       crankshaft. The camshaft has one
                                       exhaust and one intake lobe per
                                       cylinder.
                                       The two exhaust valves are actuated
                                       by a single exhaust lobe and the two
                                       intake valves are actuated by a single
                                       intake lobe.
                                       The camshaft bearings are lubricated
                                       by the rear cam groove. This groove
                                       receives oil from the block gallery
                                       and oil flows through the center of the
                                       camshaft to each cam bearing journal.
                  Rear Camshaft
                      Grove
                                       Gear Timing
                                       The camshaft and high pressure fuel
                                       pump are driven off the crankshaft.
                                       The timing gears are accessible
  High Pressure                        by removing the front cover. The
 Fuel Pump Gear                        camshaft, crankshaft and high
                                       pressure fuel pump all need to be
                                       timed together.
                                       Note: The fuel pump is timed so that
                                       the fuel pump stroke happens at the
                                       same time as the injection stroke.
                                       This provides a more consistent fuel
 Camshaft Gear                         delivery.
                                       See the Workshop Manual for the
                                       specific procedure for timing the
                                       crankshaft, camshaft and fuel pump.
Crankshaft Gear
                                  19
                                    LOWER ENGINE COMPONENTS
Crankshaft Main and Connecting
                                                                          Crankshaft
Rod Bearings                                                             Main Bearings
Both the crankshaft main and
connecting rod bearings are color
coded and a tangless design.
The lower half of the crankshaft main
bearings are a dark gray color while
the upper half is a bright metal with a
lubrication groove and a slot for the oil
to flow through.
The upper half of the connecting rod
bearings are dark gray while the lower
half is a bright metal with no grooves.
                                                        Connecting Rod
                                                           Bearings
                                               Rear Crankshaft
                                                    Seal
                                            Front Crankshaft
                                                  Seal
                                                        20
LOWER ENGINE COMPONENTS
                           Vacuum Pump
                           The vacuum pump is located on the
                           upper portion of the front cover and is
                           driven by the high pressure fuel pump.
                           Vacuum is used for the EGR cooler
                           bypass system and the wastegate
                           control system.
                           Oil Pan
                           The oil pan provides the mounting
                           locations for the oil cooler and the oil
                           filter adapter. The oil filter adapter is
                           mounted to the right rear of the oil pan
                           and contains the oil pressure switch
                           and the Engine Oil Temperature (EOT)
                           sensor. The oil cooler is mounted
                           to the left rear of the oil pan. The oil
                           cooler is a coolant-to-oil cooler.
                           Oil Cooler
                           The oil cooler is mounted to the
          Oil Cooler Nut   outside of the left side of the oil pan.
                           It is held onto the oil pan by bolts on
                           the outside of the pan and a nut on the
                           inside of the pan seals the center ports
                           of the cooler.
                           Note: The lower oil pan must be
                           removed to gain access to the oil
                           cooler nut.
          21
                                   LOWER ENGINE COMPONENTS
Oil Cooler Passages
The oil travels through the oil pan from
the oil pump to the cooler, back into         Oil Cooler        Oil Cooler
the pan to the oil filter, then back to the      Inlet            Outlet
pan and feeds the engine.
                                                              Coolant
                                                             Crossover
                                                       22
                                              COOLING SYSTEM
The 6.7L Power Stroke® diesel engine has two separate cooling systems:
•	 The engine cooling system, called the primary or high temperature cooling system,
•	 The powertrain secondary cooling system, a low temperature system which cools the Charge Air Cooler (CAC), fuel
   cooler, EGR cooler and transmission oil cooler.
Both cooling systems have their own radiator, belt-driven coolant pump, thermostats and degas bottle.
Motorcraft® Specialty Orange coolant mixed with distilled water is the only coolant to use in the 6.7L Power Stroke®
diesel engine. Corrosion resistance needs to be checked at specific intervals using Motorcraft® test strip kit. Consult the
workshop manual for details.
                                                             23
                                            COOLING SYSTEM
Primary Cooling System
Degas Bottle
Thermostats
Water Pump
    From EGR
      Block                                      Heater Core
                                                    Inlet
                                                            24
                             COOLING SYSTEM
                                                       Coolant System Flow (Back of Front
                                                       Cover)
                                       Inlet for       •	 Coolant is sealed via rubber O-ring
     Inlet for                    Cylinders on Right
Cylinders on Left                                         seals.
                                                       •	 Coolant is directed through two
                                                          passages in the front cover. One for
                                                          the right bank of cylinders and one
                                                          for the left bank of cylinders.
                                                       •	 During warm up the thermostat
                                                          blocks the coolant flow to the
                                                          radiator and the coolant is routed
                                                          back to the pump through the
                                                          bypass circuit.
                                                       •	 At normal operating temperature
                                                          the thermostats are completely
                                                          opened and the coolant is routed to
                                                          the pump via the radiator.
                                                       Primary Thermostat
                                                       The primary thermostat has two
                                                       thermostatic devices in one assembly.
                                   ECT Sensor
                                                       It is located in the coolant crossover at
                                                       the front of the engine. The thermostat
                                                       regulates the engine coolant
                                                       temperature by controlling the flow of
                                                       coolant through the primary radiator.
                                                       The two thermostatic devices do not
                                                       open at the same coolant temperature.  
                                                       The opening temperatures are
                                                       staggered by design, one opens at
                                                       90°C (194°F), other opens at 94°C
                                                       (201°F).
                                   25
                                           COOLING SYSTEM
Engine Oil Cooler
The engine oil cooler is located on the
left side of the engine oil pan. Coolant
flows from the lower rear of the block
through the heat exchanger and back
to the coolant pump inlet at the lower
hose connection.
                                                 26
                                             COOLING SYSTEM
Powertrain Secondary Cooling System
                                                                    Radiator
                                                                                                             Degas
                                                                                                             Bottle
CAC
Thermostat
                         EGR Cooler
                                                                     Coolant Pump
        Fuel Cooler
Thermostat
                                                                Transmission
                                                                  Oil Cooler
Powertrain Secondary Cooling System Flow
•	 The powertrain secondary cooling system cools the             first stage of cooling.
   following components:
                                                              •	 The inlet for the CAC and the fuel cooler comes from the
   –– Charge Air Cooler (CAC)                                    left side of the radiator after both stages of cooling.
   –– fuel cooler                                             •	 The outlet for all heat exchangers returns to the degas
   –– EGR cooler                                                 bottle.
   –– transmission oil cooler
•	 The coolant is drawn into the inlet of the coolant pump
   from the degas bottle. The coolant exits the pump and is
   routed to the radiator.
•	 The radiator for the powertrain secondary cooling system
   has two stages.
•	 The inlet for the transmission oil cooler and the EGR
   cooler comes from the right side of the radiator after the
                                                           27
                                         COOLING SYSTEM
Charge Air Cooler (CAC)
The 6.7L CAC is an air-to-coolant
heat exchanger. This allows for more
cooling capacity in a smaller under
hood space.
ECT2
                                                   28
             COOLING SYSTEM
                              Transmission Cooler
                              The transmission cooler for the 6R140
                              transmission is located on the right
                              front inner frame rail.
                              Fuel Cooler
                              The fuel cooler is located on the left
                              frame rail between the engine and
                              the Diesel Fuel Conditioning Module
                              (DFCM). It cools the return fuel before
                              it is sent to the DFCM.
                              Secondary Thermostats
                              The high temperature thermostat
                  Left Tank   is located on the right side of the
                              secondary radiator and regulates
                              the upper radiator temperature to
                              approximately 60°C (140°F).
                              The low temperature thermostat
                              is located on the left side of the
                              secondary radiator and regulates
                              the lower radiator temperature to
                              approximately 45°C (113°F).
Right Tank
                   29
                                            COOLING SYSTEM
Secondary Coolant Pump
The secondary coolant pump is
located on the right front of the engine.
                                                  30
COOLING SYSTEM
                 Radiators
                 The coolers that are located at the
                 front of the grille opening include:
                 •	 primary radiator.
                 •	 secondary radiator.
                 •	 air conditioning condenser.  
                 •	 power steering cooler.
                 The secondary radiator is located
                 in front of the primary radiator to
                 allow the powertrain secondary
                 cooling system to operate at a lower
                 temperature than the primary cooling
                 system.
                 Quick-Connect Fittings
                 Both cooling systems use unique
                 quick-connect fittings on the larger
                 coolant hoses and standard style
                 clamps on the smaller hoses.
      31
NOTES
  32
                                           LUBRICATION SYSTEM
                                                               33
                                             LUBRICATION SYSTEM
Oil Pump
The gerotor style oil pump is mounted
to the back side of the front cover.
Note: The front cover must be
replaced to service the oil pump.
                                                     34
       LUBRICATION SYSTEM
                            Cylinder Head Lubrication
                            There is an oil manifold in each
                            cylinder head that sprays oil onto the
                            rocker arms and valve springs for
                            cooling and lubrication.
Oiling Manifold
                            Oil Cooler
                            The oil cooler is mounted on the oil
                            pan of the engine and uses engine
                            coolant to dissipate heat from the
                            engine oil.
                            The coolant and oil are separated by
                            multiple plates that create passages in
                            the oil cooler.
                            After oil has been cooled, it exits the
                            oil cooler and travels through the oil
                            pan to the oil filter.
                            Oil Filter
                            The oil filter is a spin-on style mounted
                            on the right side of the oil pan.
                  35
NOTES
  36
                                       AIR MANAGEMENT SYSTEM
Intake Side
Air is drawn through the air filter then past the Mass Air Flow (MAF) and Intake Air Temperature (IAT) sensors. The
MAF sensor measures the mass of the air entering the engine and IAT obtains the temperature. Next, the air enters
the compressor side of the turbocharger through the lower intake manifold. The air is compressed above atmospheric
pressure. The compressing process causes the air to heat up. Directing the air to an air to coolant Charge Air Cooler
(CAC). From the CAC the air passes the CAC temperature sensor and through the intake throttle body and into the other
side of the lower intake manifold. Inside the lower intake manifold the air mixes with EGR gases (if EGR valve is open),
travels to the upper intake manifold, and through the right and left side rocker covers to the intake ports of the cylinder
heads.
Exhaust Side
Exhaust gases exit the exhaust ports into the inboard exhaust manifolds. Exhaust gases are directed to the dual inlet
of the turbo via the right and left side up-pipe. The exhaust spins the turbine wheel inside the turbocharger. The turbine
wheel spins the compressor wheel(s) via their common shaft. Some of the exhaust from the passenger side manifold is
directed to the EGR valve through the EGR inlet pipe. When the EGR valve is being operated, exhaust flow goes through
the valve then either through the EGR cooler or bypassing the cooler. This is done by the EGR cooler bypass valve. The
exhaust gas enters the lower intake manifold and combines with the fresh air.
                   LEGEND
                 INTAKE
                 EXHAUST                                                                   18
                 COOLED EXHUAST                     1
                 CRANKCASE GASES                                             19
                                            3                                                                 17
                                   4
                  5
                                        9                                  12
                             6                                                                           16
8 11
                                                                                                              15
                                            7
                                                        10                                         14
                                                                                   13
                                                             37
                                     AIR MANAGEMENT SYSTEM
Air Inlet Components
Air Filter
The air filter is located on the
passenger side of the engine
compartment in front of the battery.
The air filter housing includes a non-
electrical filter minder to measure inlet
restriction. When the filter element
becomes contaminated beyond
useful limits, the filter minder visually
indicates the need for replacement.
                                               38
                 AIR MANAGEMENT SYSTEM
                                            Chassis Cab Turbocharger (Narrow
                                            Frame)
                                            The chassis cab use a standard
                                            Variable Geometry Turbocharger
                                            (VGT) operated with engine oil
                                            pressure that is controlled by the
                                            PCM. This turbocharger does not
                                            incorporate a wastegate.
CAC Inlet
CAC Outlet
                          39
                                     AIR MANAGEMENT SYSTEM
Lower Intake Manifold
                                                                                            Air to Upper
The lower intake manifold is on the top           Air Mufflers                            Intake Manifold
of the engine and intake air passes
through it twice. The first time it flows
                                                Air to
through the lower intake manifold           Turbocharger
before going to the turbocharger inlet.     Compressor
Crankcase vapors are pulled into the
lower intake manifold with the air on its
way to the turbocharger.
                                                                                              Air From
                                                                                              Air Filter
                                                                               Air From
                                                                              EGR Valve
                                                           40
AIR MANAGEMENT SYSTEM
                   Intake Manifold/Valve Cover
                   The intake manifold/valve cover for
                   each cylinder head are incorporated
                   into one piece. The air flows from the
                   upper intake manifold into the top
                   of the valve cover and across to the
                   intake ports.
         41
                                    AIR MANAGEMENT SYSTEM
Glow Plug System
Glow Plug Control Module (GPCM)
The GPCM is located under the
passenger side battery box.
The glow plug system is electronically
controlled by the PCM. The PCM
monitors the ambient temperature,
ECT and BARO sensors to control
glow plug operation.
The GPCM controls the glow plugs
and the reductant system heating
elements.
When required, the PCM supplies
a signal to the GPCM which in turn
supplies current to the glow plugs.
Glow Plugs
The glow plugs are mounted in the
cylinder heads and are accessible
through the valve cover.                                                                        Glow Plugs
The GPCM supplies the required
current to each glow plug, based on
commands from the PCM. Ground is
provided through the glow plug body
to the cylinder head.
                                                              0                                                                                  -200
                                                                   0          5           10         15          20           25          30
                                                                   Time in Seconds                                      Glow Plug Temperature
                                                                                                                        Glow Plug Current Flow
                                                                          42
                                    AIR MANAGEMENT SYSTEM
DualBoost Variable Geometry Turbocharger (VGT)
Turbocharger control is based off an air system model that produces a desired intake pressure to meet the power
requirements requested by the operator.. The PCM commands the VGT control valve by a feedback loop on the intake
pressure to achieve the desired intake pressure to meet the driver’s needs (pedal position, engine load). The air system
model considers engine temperature, air temperature, EGR operation, RPM, and engine load.
The turbocharger on pickup box models have a wastegate. The PCM controls the wastegate solenoid to supply vacuum
to the actuator. When intake pressure is greater than desired and the VGT has commanded the vanes to the full open
position the wastegate opens allowing exhaust gases to bypass the turbine fins, reducing exhaust pressure thus reducing
intake pressure.
                                                                                                         High Speed
                                        VGT Solenoid                                                       Air Inlet
VGT Vanes
                                                                                  Intake Compressors.
                                                                                  The DualBoost VGT has two intake
                                                                                  compressors and one exhaust turbine
                                                                                  on a common shaft.
                                                           43
                                     AIR MANAGEMENT SYSTEM
VGT Closed
When the VGT is closed it maximizes
the use of the energy that is available
at low speeds. Closing the VGT
accelerates exhaust gas flow across
the vanes of the turbine wheel. This
allows the turbocharger to behave
as a smaller turbocharger. Closing
the vanes also increases the exhaust
pressure in the exhaust manifold,
which aids in pushing exhaust gas into
the intake. This is also the position for
cold ambient warm-up.
VGT Open
During engine operation at high
engine speeds and load, there is
a great deal of energy available in
the exhaust. Excessive boost under
high speed, high load conditions can
negatively affect component durability.
Therefore, the vanes are commanded
open preventing turbocharger
overspeed. Essentially, this allows
the turbocharger to act as a large
turbocharger.
                                               44
               AIR MANAGEMENT SYSTEM
                                            VGT Actuator
                                            The 6.7L VGT actuator uses engine
                                            oil pressure on a piston to move
                                            the vanes on the exhaust turbine.
                                            The VGT actuator is commanded
                                            by the PCM, based on a desired
                                            MAP pressure. This actuator meters
                                            engine oil to either side of the piston.
                                            This design feature reacts quickly to
                                            changes in demand based on driving
                                            conditions. When one side of the
                                            piston is pressurized, the opposite
                                            side is vented.
                                            Coolant Passages
                                            The turbocharger is cooled using
                                            coolant from the primary cooling
                                            system. Coolant enters the
   Oil Inlet                 Coolant        turbocharger from the block on the
                              Inlet         bottom of the turbocharger and
                                            flows through and out the top of the
                                            turbocharger through a line back to the
                                            coolant crossover tube.
Oil Drain
                             Coolant Weep
                               Passage
                        45
                                    AIR MANAGEMENT SYSTEM
Exhaust Gas Recirculation (EGR)
The EGR system allows cooled (inert) exhaust gases to re-enter the combustion chamber, which lowers combustion
temperatures and Oxides of Nitrogen (NOx) emissions.
EGR system control is based off an air system model to estimate the percentage of exhaust gas in the cylinder. The
PCM looks at engine temperature, intake pressure, exhaust pressure (EP), RPM, and engine load to determine the EGR
flow rate. The ratio of MAP and EP is used by the PCM to estimate a desired EGR valve position. The desired position is
compared to the actual and the duty cycle is adjusted to meet that desired position for the required EGR flow rate. If the
rate is not achieved with EGR valve position, the intake throttle body closes to a desired position, reducing intake manifold
pressure. Reducing the intake manifold pressure increases the pressure ratio allowing more exhaust to fill the intake
manifold at a given EGR valve position. As more exhaust gas is introduced into the intake manifold the amount of air
measured by the Mass Air Flow (MAF) sensor is decreased.
The 6.7L has a hot side EGR valve due to it being before the EGR cooler. Once past the EGR valve, the exhaust gas is
either directed through the EGR cooler or bypasses the EGR cooler. This is done by the PCM controlling the EGR cooler
bypass solenoid which turns vacuum on or off to the actuator on the bypass door. The EGR outlet temperature (EGRT)
sensor measures the temperature of the exhaust gas leaving the system for cooler effectiveness and bypass control.
                            EGR Cooler
   EGR Valve              Bypass Solenoid
    Actuator                                      EGR Cooler
                                                Bypass Actuator                    Secondary
                                                                                  Coolant Inlet
ECT2
                                                                    Secondary
                                                                   Coolant Outlet
   Exhaust Gas
      Inlet
                                                EGR Outlet
                                                             46
                       AIR MANAGEMENT SYSTEM
                                                     EGR Valve
                                                     The EGR valve receives a duty cycle
                                                     signal from the PCM and sends
                                                     a variable voltage signal from the
                                                     Exhaust Gas Recirculation Valve
                                                     Position (EGRVP) sensor back to
                                                     the PCM to indicate actual position.
                                                     Internally, it has two valves connected
                                                     by a common shaft. Exhaust gases
                                                     are routed from the right exhaust
                                                     manifold to the center of the valve.  
                                                     When the valve is opened, exhaust
                                                     gases flow out the top and bottom
                                                     poppet valves either through the EGR
                                                     Cooler and to the intake manifold or
                                                     directly to the intake manifold if the
                                                     EGR cooler bypass valve is in bypass
                                                     position.
                                                     EGR Cooler
Powertrain Secondary
  Cooling System                                     The EGR system uses an EGR cooler
                                                     after the EGR valve. This keeps the
                                                     EGR valve cleaner than previous
                                                     engines.
                                                     The EGR cooler is located on the right
                                                     valve cover, for easier service.
                                                     The cooler EGR temperature reduces
                                                     NOx emissions.
                                   Primary Cooling
                                       System
                                    47
                                    AIR MANAGEMENT SYSTEM
EGR Powertrain Secondary Coolant
Flow                                       Secondary Coolant Flow
The second part of the EGR cooler is
cooled by the powertrain secondary
cooling system.
An internal air-to-coolant heat
exchanger absorbs heat from the
exhaust gases and dissipates heat to
the atmosphere through the powertrain
secondary radiators.
EGR Flow
                                                                        EGR Cooler Flow
The exhaust gas enters through the
EGR valve and then goes through the
EGR bypass valve. As the exhaust
gas enters the EGR cooler, it is first
cooled by the primary cooling system.
It flows through the secondary EGR
cooler where it is cooled further before
exiting the EGR cooler and entering
                                                                    1
the intake air system.
                                                     48
               AIR MANAGEMENT SYSTEM
                                         EGR Cooler Bypass Valve
 EGR Cooler
Bypass Valve                             The EGR cooler bypass valve alters
                                         the flow of EGR gases to increase the
                          EGR Cooler     temperature of the gas at low engine
                        Bypass Passage   speeds. The vacuum controlled valve
                                         is solenoid controlled by the PCM.
                                         If the PCM determines that it does
                                         not need to cool the exhaust gas,it
                                         commands the EGR solenoid to
                                         close the bypass valve and route the
                                         exhaust gas directly to the intake air
                                         system.
ECT2
                              49
NOTES
  50
                                                                   FUEL SYSTEM
At key on, the fuel pump within the Diesel Fuel Conditioning Module (DFCM) is turned on and the low pressure fuel
system is pressurized. If the engine is not started, the pump runs for up to 30 seconds. The PCM obtains information from
the Ambient Air Temperature (AAT), Engine Coolant Temperature (ETC) , Engine Oil Temperature (EOT) , and Fuel Rail
Temperature (FRT) sensors for fuel delivery calculations. The Volume Control Valve (VCV) and Pressure Control Valve
(PCV) are open.
During engine cranking the PCM identifies Top Dead Center (TDC) within approximately 120 degrees of crankshaft
rotation and PCV is closing, allowing fuel pressure in the rail to achieve the calibrated value. This allows the engine to
start very quickly.  
Once the Fuel Rail Pressure (FRP) sensor detects the required fuel pressure, the PCM begins fuel injection operation to
meet the desired idle RPM based upon the temperature sensors and engine load. During this initial start up mode, the
high pressure fuel system is run in PCV mode for a calibrated amount of time. The VCV is set to a specified point while
PCV is duty cycled to meet the desired fuel rail pressure.
The high pressure fuel system operates in PCV mode until a calibrated fuel temperature and time is achieved.
In VCV mode the fuel volume entering the high pressure fuel pump is adjusted by the VCV to meet the required fuel rail
pressure while still being trimmed by the PCV. VCV mode is a more efficient operating mode because only the amount of
fuel required for combustion is being compressed by the pump and sent to the fuel rails.
During acceleration, the VCV and PCV are commanded to meet the driver’s demand (accelerator pedal input/engine
load). The PCM’s commands to the VCV and PCV are based upon: FRT, ECT, EOT, ATT, engine load, and regeneration
state.
On deceleration, the VCV is closed and the PCV is opening to max position to reduce fuel pressure. When RPM is
approaching the desired idle speed, the VCV begins to open to prepare for injector usage.
During regeneration, the left side injectors perform post injection. The right side injectors do not provide fuel for
regeneration because right side cylinders supply exhaust gas to the EGR valve and EGR cooler.
Under certain conditions, like battery disconnect and fuel system reset, the fuel system operates in Adaptive PCV (APCV)
mode on the first start. In the APVC mode, the PCM is learning the duty cycle needed for the PCV to achieve the desired
fuel pressure.
                                                                                                  High pressure fuel system operating mode:
                                                                                                  •	 High pressure fuel system runs in PCV mode at
                                                                                                     start up until a calibrated time and temperature
                                                                                                     have been met.
                                                                                                  •	 Thermal recirculation valve is fully open up to
                                                                                                     between 24-27°C (75 - 80°F) and fully closed at
                                                                                                     38°C (100°F) (all fuel goes back to tank)
                Injectors
                                                                                   Fuel Delivery
                                                                                   Pressure
                                                       High Pressure               Sensor                                             Thermal Recirculation Valve
                                                       Fuel Pump
                                                                                                                                     DFCM
                  Rail
                                                                               Secondary                Fuel Cooler
                                                                               Fuel Filter
                                                                       T
                                                                       U
                                                                           T
                                         F                                     4µm Filter
                                                                               Water Seperation                       Low Pressure      10µm Primary
       U
           P      Rail                                                                                                 Fuel Pump          Fuel Filter
Injectors
                         High Pressure
                         Internal Low Pressure
                         Vehicle Low Pressure                                  Engine Components         Vehicle Components
                                                                                  51
                                                   FUEL SYSTEM
Fuel Supply System
•	 The DFCM includes the following components:
   –– low pressure fuel pump
   –– 10 micron primary fuel filter
   –– thermal recirculation valve
   –– water fuel separator (~200ml)
   –– Water in Fuel (WIF) sensor
   –– water drain (manual operation)
•	 After the fuel is conditioned by the DFCM, the clean pressurized fuel is sent to the engine mounted fuel filter assembly
   where particles larger than 4 micron are filtered out of the fuel. After the fuel is filtered, it is routed to the high pressure
   fuel pump.
                                                                52
                FUEL SYSTEM
                                   Water Drain Valve
                                   The water drain valve is located on the
                                   bottom of the DFCM.
                                   To drain water that has accumulated in
                                   the DFCM, turn the drain valve to the
                                   open position.
                     Water Drain
                       Valve
Water In Fuel
  Sensor
                    53
                                          FUEL SYSTEM
Secondary Fuel Filter Assembly
from the Factory
The secondary fuel filter that is
equipped on the vehicle from the
factory has three ports. The third port
is used during the assembly process.
The service part only has two ports:
the inlet from the DFCM and the outlet
to the VCV inlet which is mounted on
the high pressure fuel pump.
                                               54
                   FUEL SYSTEM
                                 Fuel Rail Temperature (FRT)
                                 The FRT is mounted in the fuel line
Fuel Temperature                 that runs between the secondary fuel
     Sensor
                                 filter and the high pressure fuel pump.
                                 It is green in color.
                                 The PCM monitors the temperature of
                                 the fuel using the FRT before the fuel
                                 enters the high pressure fuel pump.
                                 Fuel temperature effects fuel viscosity.
                                 The PCM uses this information for
                                 more precise fueling no matter what
                                 the fuel temperature.  
                                 Fuel Cooler
                                 A fuel cooler is located on the left
                                 frame rail forward of the DFCM. The
                                 black fuel line is used for fuel return
                                 from the engine to the cooler. The
                                 gray fuel line returns fuel from the
                                 cooler to the DFCM. Depending on
                                 the temperature of the fuel from the
                                 injectors, the fuel cooler can be used
                                 to cool or heat the fuel going back to
                                 the DFCM. The powertrain secondary
                                 cooling system provides the coolant
                                 for the fuel cooler.
                       55
                                                  FUEL SYSTEM
Biodiesel
                                            •	 be alert to fuel gelling/waxing.             standards.
The 6.7L Power Stroke® diesel engine
may be operated on diesel fuels             •	 the fuel system must be flushed out       •	 do not use raw oils, fats or waste
containing up to 20% biodiesel, also           with regular diesel fuel if the vehicle      cooking greases.
known as B20.                                  is going to be in storage for more        Use of fuels containing more than 20%
                                               than a month                              biodiesel can damage engine and fuel
To help achieve acceptable engine
performance and durability when using       •	 only use biodiesel fuel of good           system components, resulting in a
biodiesel in your vehicle:                     quality that complies with industry       non-warranty condition.
                                                                3
                                                                                                       6         7
                                                                            4              5
                                                               56
FUEL SYSTEM
              High Pressure Fuel Pump
              The high pressure fuel pump is
              mounted in the front valley of the
              engine and is gear driven by the
              camshaft.
              The high pressure fuel pump is
              timed to the crankshaft and camshaft
              to optimize the effects of the high
              pressure fuel pulses.
              The high pressure fuel pump is
              lubricated by diesel fuel.
              Piston Assemblies
              The pistons are actuated via the
              actuating lobes and are returned to
              rest via spring pressure. The pistons
              receive fuel from the through a one-
              way check valve. Fuel is drawn
              into the cylinder while the piston is
              returning to rest. The fuel flow to the
              cylinders of the pump are metered by
              the Volume Control Valve (VCV).
    57
                                            FUEL SYSTEM
Piston Assembly Check Valves                                                     High Pressure
The outlet check valve closes while          Low Pressure                         Check Valve
fuel is being drawn in due to a                Fuel Inlet
pressure difference on the two sides of
the check valve. Once the piston starts
its compression stroke, the inlet check
valve closes via the spring and fuel
pressure and the outlet check valve
opens due to increasing fuel pressure,
forcing the check valve off its seat.
                                                  58
                                      FUEL SYSTEM
                                                               Fuel Rail Pressure (FRP) Sensor
                                                               The FRP is threaded into the front
                                                               of the left fuel rail. The FRP sensor
                                                               is a three-wire variable capacitance
                                                               sensor. The PCM supplies a 5 volt
                                                               reference signal which the FRP sensor
                                                               uses to produce a linear analog
                                                               voltage that indicates pressure. The
                                                               FRP sensor actively monitors fuel rail
                                                               pressure to provide a feedback signal
                                                               to the PCM.
                                               Fuel Rail
                                           Pressure Sensor
                                                               Fuel Rails
                                                               The fuel rails on the 6.7L Power
                                                               Stroke® diesel engine are on the
   Right Fuel Rail
                                                               outside of the valve covers. The left
                                                               fuel rail has the FRP sensor and the
                                               PCV Solenoid    PCV solenoid. The right fuel rail does
                                                               not have any sensors or solenoids.
                                                               The left fuel rail is longer due to a
                         Diverter Volume                       diverter volume.
FRP Sensor
                                               59
                                              FUEL SYSTEM
Piezo Fuel Injectors
There are eight fuel injectors; four
mounted on each cylinder head.
They are serviced without removing
the valve covers. The Injector
Quantity Adjustment (IQA) must be
programmed into the PCM when a
new injector is installed.
The injector is a 19 mm piezo-actuated
injector with an 8 hole nozzle.
Each fuel injector is retained with a
single clamp and bolt through the
rocker cover to the cylinder head.
A stepped copper gasket is used
to better distribute the sealing load
between the cylinder head and
injector. This allows heat to transfer
from the injector nozzle to the cylinder
head. The step is installed towards the
cylinder head.
                                                       Piezo
                                                      Actuator
                                                          60
                        FUEL SYSTEM
                                      Hydraulic Coupler
      Down       Up                   The piezo stack is linked to the control
                                      valve of the fuel injector via a fuel-filled
                                      hydraulic coupler. The upper piston of
                                      the coupler is a larger diameter than
                                      the lower piston. This difference in
                                      diameter causes an increase in the
     Upper     Upper                  linear movement of the lower piston
     Piston    Piston                 (more travel).
                                      Note: If the hydraulic coupler is not full
                                      of fuel, the lower piston will not move
                                      and fuel will not be injected into the
                                      combustion chamber. The hydraulic
                Fuel                  coupler is supplied with fuel by the low
      Fuel                            pressure fuel pump when the key is
                                      turned on and from return fuel when
                                      the engine is running.
     Lower     Lower
     Piston    Piston
                                      Control Valve
                                      The lower hydraulic coupler piston
                                      moves the control valve down to
              Closed                  relieve high pressure from the top
                                      of the nozzle needle (the control
                                      chamber).
                                      When the control valve is pushed
                                      fully down, it seals off an orifice in
                                      the intermediate plate, stopping that
                                      fuel flow path of high pressure fuel to
                                      the top of the nozzle needle. Fuel is
                                      allowed to flow past the control valve,
                                      also removing pressure from the top of
                                      the nozzle needle.
Control        Coupler
 Valve          Piston
Open
                            61
                                                FUEL SYSTEM
Injector Nozzle Needle
When the high pressure is relieved
from the top of the nozzle needle, high
pressure on the lower surfaces force
the needle up and allows fuel to be
sprayed into the combustion chamber.               Open                              Closed
When the control valve is released,
spring pressure and high pressure fuel
moves the needle back up against
the seat in the control valve housing,
sealing the nozzle control chamber.                                Upper
High pressure fuel is again applied to                            Surface
the top of the nozzle needle, pushing
the needle down to stop fuel flow into
the combustion chamber.
                                                                   Lower
                                                                  Surface
Injector Quantity Adjustment (IQA)         with each service replacement injector.    The new injector IQA sticker must be
Code                                       Refer to both the factory label and        affixed next to the old sticker.
                                           the individual service labels to obtain    Note: If an injector is being swapped
Each injector has a unique 10
                                           the latest IQA data. If the labels are     to a different cylinder the IQA number
digit code representing the flow
                                           missing or damaged retrieve the IQA        must be programmed.
characteristic of that injector. The IQA
                                           data from each injector head.
code is located on each injector head
and is also printed on a factory label     When an injector is replaced, program
located on the engine. The factory         the IQA code for the injector using
installed label indicates the IQA data     the IDS. The IDS will automatically
for all the original injectors installed   clear the keep alive memory values
at the factory. In addition, there are     associated with the old injector when
individual injector IQA labels provided    the new injector IQA code is entered.
                                                             62
                                                                                      ELECTRICAL COMPONENTS
                                    SBF02
                                                                                                                                          CBB52
                            SBB72
5 C2280F
CBB33
CBB52
                                                                                                                                                                                                CE436
                                                                                                  S105
                                                                                                                                                                                                                             POWER
                                                                                                                                                                                                                             DISTRIBUTION/BCM
                                                                                                                                    POWER                                                               S200     CE436
                                                                                                                                    DISTRIBUTION/BCM
                                                                         CBB33
CBB33
CBB33
                                                                                                                                                             CBB52
     SBB72
CE237
                                                                                                                                                                                                CE436
                                                                                                                                                                      POWER
                                                                                                                                                                      DISTRIBUTION/BCM
62 38 67 68 69 42 35 C1232B
                                                                                                                                                                                                                             POWERTRAIN
     KAPWR                                     PCMRC                      VPWR             VPWR                VPWR                                           ISP-R                            PCM WAKE                      CONTROL
                                                                                                                                                                                                                             MODULE (PCM)
                   70                  71                  72                    73               74      C1232B
                    GD113
GD113
GD113
GD113
GD113
G105
                                                                                                                               63
                                    ELECTRICAL COMPONENTS
Pressure Sensors
Barometric Pressure (BARO)                                                                      Barometeric Pressure (BARO) Sensor
                                                                 5
The BARO sensor is internal to the
PCM.
The PCM supplies a 5 volt reference                              4
signal (VREF) which the BARO sensor
uses to produce a linear analog
voltage that indicates pressure.                                 3
The PCM uses the BARO sensor to
                                                      Voltage
determine atmospheric pressure for
fuel control, timing, and turbocharger                           2
control.
IDS: BARO (volts) and BARO
(pressure)                                                       1
                                                                 0
                                                                     5            7        9            11            13              15        17             19
                                                                                                              Pressure (psi)
0.5
                                                                 0
                                                                         0            10          20                30                40             50             60
                                                                                                            Manifold Pressure (psi)
                                                   2.5
delta pressure calculation.
                                                      2
IDS: EP (pressure) and EP_V (volts)
                                                   1.5
0.5
                                                      0
                                                             0               10       20   30          40         50           60          70   80        90        100
                                                                                                        Exhaust Pressure (psi)
                                                                                      64
                                                                 ELECTRICAL COMPONENTS
                                                     Fuel Rail Pressure (FRP) Sensor                                           Fuel Rail Pressure (FRP)
                     5                                                                                                         The FRP is a 3-wire variable
                                                                                                                               capacitance sensor. The FRP
                 4.5
                                                                                                                               produces a linear analog voltage that
                     4                                                                                                         indicates pressure of the high pressure
                                                                                                                               fuel system.
                 3.5
                                                                                                                               The PCM monitors fuel rail pressure
                     3                                                                                                         as the engine is operating to control
Voltage
                 2.5
                                                                                                                               fuel pressure. This is a closed loop
                                                                                                                               function which means the PCM
                     2                                                                                                         continuously monitors and adjusts for
                 1.5                                                                                                           ideal fuel rail pressure determined by
                                                                                                                               conditions such as load, speed and
                     1
                                                                                                                               temperature.
                 0.5                                                                                                           IDS: FRP (volts) and FRP_A
                     0
                                                                                                                               (pressure)
                         0        5000             10000             15000                20000          25000         30000
                                                                Fuel Pressure (psi)
                                             Diesel Particulate Filter (DPF) Pressure Sensor                                   Diesel Particulate Filter (DPF)
                 5
                                                                                                                               Pressure
                                                                                                                               The DPF sensor is a 3-wire variable
                                                                                                                               capacitance sensor. The PCM
                 4                                                                                                             supplies a 5 volt reference (VREF)
                                                                                                                               signal which the DPF pressure sensor
                                                                                                                               uses to produce a linear analog
                 3                                                                                                             voltage that indicates pressure.
Voltage
                                           Command to PCM
IDS: LP_FUEL_SW (low/not low)
                                                            0        10         20         30            40            50            60         70         80
                                                                                                   Fuel Pressure (psi)
refrigerant. 2
                                                             0
                                                                 0   50   100        150         200        250          300   350        400        450   500
                                                                                                       Pressure (PSIA)
Temperature Sensors
Temperature sensors are thermistor devices in which resistance changes with temperature. The electrical resistance of a
thermistor decreases as the temperature increases, and resistance increases as the temperature decreases. The varying
resistance affects the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding
to temperature. Unless specified otherwise, all the temperature sensors operate this way.
                                                                          66
                                     ELECTRICAL COMPONENTS
                            Engine Oil Temperature (EOT)                                Engine Oil Temperature (EOT)
           5                                                                            The EOT sensor is a 2 wire thermistor-
                                                                                        type sensor. The PCM applies 5 volts
          4.5
                                                                                        to the EOT sensor circuit. The sensor
           4                                                                            changes the internal resistance as
                                                                                        engine oil temperature changes. The
          3.5
                                                                                        EOT sensor is used in operation of the
           3                                                                            cooling fan, VGT, and engine control
                                                                                        plus diagnostics.
Voltage
          2.5
                                                                                        The EOT sensor signal allows the
           2
                                                                                        PCM to compensate for oil viscosity
          1.5                                                                           variations due to temperature changes
                                                                                        in the operating environment.
           1
                                                                                        IDS: EOT (volts) and EOT
          0.5
                                                                                        (temperature)
           0
            -50   0   50      100        150          200        250        300   350
                                    Temperature (Deg F)
          2.5
                                                                                        operation.
           2
                                                                                        The ECT sensor measures
          1.5                                                                           temperature of the primary cooling
                                                                                        system.
           1
                                                                                        IDS: ECT (temperature) and ECT_V
          0.5
                                                                                        (volts)
           0
            -50   0   50      100        150          200        250        300   350
                                    Temperature (Deg F)
                                                                       67
                                   ELECTRICAL COMPONENTS
 Ambient Air Temperature (AAT)                                                  Ambient Air Temperature (AAT)
Sensor
                                                     5
The AAT sensor is a 2-wire thermistor-
type sensor. The PCM applies 5 volts
to the AAT sensor circuit. The sensor                4
changes the internal resistance as the
ambient air temperature changes.
The AAT sensor is used as an input                   3
                                           Voltage
into the engine controls, particularly,
engine coolant fan operation,
glow plug system control and for                     2
diagnostics.
The AAT sensor is located in the                     1
passengers mirror.
IDS: AAT (temperature) and AAT_V
(volts)                                              0
                                                         -50        0               50                   100              150         200
                                                                                         Temperature (Deg F)
(volts) 1
0.5
                                                         0
                                                          -50   0        50              100            150         200         250   300
                                                                                          Temperature (Deg F)
                                                    0
                                                        -50         0               50                   100              150         200
                                                                                         Temperature (Deg F)
                                                                    68
                                                             ELECTRICAL COMPONENTS
                                                     Fuel Temperature Sensor                                                   Fuel Rail Temperature (FRT)
              5
                                                                                                                               The FRT is a 2 wire thermistor-type
                                                                                                                               sensor. The PCM supplies 5 volts to
          4.5
                                                                                                                               the FRT sensor circuit. The sensor
              4                                                                                                                changes the internal resistance as the
                                                                                                                               fuel temperature changes.
          3.5
                                                                                                                               The PCM uses the fuel temperature
              3                                                                                                                for fuel delivery correction and
                                                                                                                               determine fuel pressure control mode
Voltage
          2.5
                                                                                                                               (PCV or VCV mode).
              2
                                                                                                                               IDS: FRT (volts) and FRT_A
          1.5                                                                                                                  (temperature)
              1
0.5
              0
               -50        0         50           100             150          200             250          300         350
                                                            Temperature (Deg F)
                                                                                                    69
                                         ELECTRICAL COMPONENTS
Position Sensors
Exhaust Gas Recirculation Valve                                                                             EGR Valve Position (%) vs. Voltage
Position (EGRVP)                                                 5
                                                       Voltage
voltage indicating EGRVP.
                                                                 2
The PCM uses the EGRVP sensor to
determine EGRVP and compares it to
the calculated desired position.
                                                                 1
IDS: EGRVP (volts) and EGR_A_ACT
(%)
                                                                 0
                                                                     0           10         20         30         40         50         60     70         80           90             100
                                                                                                                        EGR Position (%)
1 5 10 15 20 25 30 35 40 45 50 55 60
Cylinder 8 1 3 7
0 or 360
1 5 10 15 20 25 30 35 40 45 50 55 60
Cylinder 2 6 5 4
                                                                                          70
                                    ELECTRICAL COMPONENTS
                       Accelerator Pedal Position (APP)                      Accelerator Pedal Position (APP)
             90                                                              The APP is a 2-track position pedal.
                                                                             The pedal has 2 potentiometers
             80
                                                                             providing pedal position to the PCM.
             70                                                              This is a safety feature.
                                                                             IDS: APP1 (volts) and APP1 [APP_D]
             60
                                                                             (%)
                                                                             IDS: APP2 (volts) and APP2 [APP_E]
Percentage
             50
                                                                      APP1
                                                                      APP2   (%)
             40
30
20
10
             0
                  Up            Pedal Position            Down
                                                                             Miscellaneous Sensors
                                                                             NOx sensor
                                                                             The NOx sensor is mounted next to
                                                                             the EGT14 sensor. The NOx sensor
                                                                             monitors the amount of NOx out of the
                                                                             tailpipe. The PCM uses the information
                                                                             to adjust how much reductant is being
                                                                             injected into the exhaust as well as
                                                                             an input for fuel trim. The information
                                                                             from the NOx sensor can also tell the
                                                                             effectiveness of the Selective Catalyst
                                                                             Reduction (SCR) system.
                                                                 71
                                    ELECTRICAL COMPONENTS
Outputs
Intake Throttle Body
The intake throttle body has an electric
DC motor to move the throttle plate.
The intake throttle body is controlled
by the PCM. The valve is powered in
both the open and closed positions.
The intake throttle body helps create
the delta pressure difference between
intake and exhaust for EGR flow,
regeneration and shutdown noise.
IDS: EGRTP_CMD (%)
EGR Valve
The EGR valve is an electric DC motor
controlled by the PCM. The valve is
powered in both the open and closed
positions.
The EGR valve is opened to allow
exhaust gases to mix with the intake
air for NOx emissions purposes.
IDS: EGR_A_CMD (%)
                                              72
ELECTRICAL COMPONENTS
                   Pressure Control Valve (PCV)
                   The PCV is threaded into the rear of
                   the left fuel rail. The PCM controls
                   the fuel rail pressure by modulating
                   the PCV which regulates the fuel rail
                   pressure.
                   The PCM regulates fuel rail pressure
                   by controlling the on/off time of the
                   PCV solenoid. A high duty cycle
                   indicates a high fuel rail pressure is
                   being commanded. A low duty cycle
                   indicates a low fuel rail pressure is
                   being commanded.
                   Fuel Injectors
                   The fuel injectors are connected to
                   the high pressure fuel rail and deliver
                   a calibrated amount of fuel directly
                   into the combustion chamber. The
                   on and off time of the fuel injectors
                   are controlled by the piezo actuator
                   device, which allows extreme
                   precision during the injection cycle.
                   The piezo actuator is commanded on
                   by the PCM during the main injection
                   stage for approximately 0-400 micro
                   seconds.
         73
                                   ELECTRICAL COMPONENTS
Variable Geometry Turbocharger
(VGT) Actuator
The VGT actuator is mounted on the
top of the turbocharger. The VGT
actuator is commanded by the PCM,
based on engine speed and load. The
magnetic field generated by this signal
moves a shaft in the control valve. A
cam follower at the end of the valve
assembly provides feedback to the
valve, allowing it to reach a neutral
position during times the vanes are not
commanded to move.
FP
                                                                                                                     INERTIA FUEL
                                                                                                                     SHUTOFF (IFS)
                                                                                                                     SWITCH
                                                                                                     2           1
                                                                                                                     1) normal
                                                                                                                     2) post-impact
FDSOM
FPM
                                                                                                                                                         FUEL
                                                                                                                                                         PUMP
                                                                                                                                              M
                                                       74
ELECTRICAL COMPONENTS
                   Glow Plug Control Module (GPCM)
                   The GPCM is mounted under the right
                   side battery box. The PCM commands
                   the GPCM to power the individual
                   glow plugs, which the GPCM does by
                   providing battery voltage. The GPCM
                   is also responsible for powering the
                   heaters used in the reductant system.
                   Cooling Fan
                   The cooling fan is mounted on the
                   front of the engine and is controlled by
                   the PCM.
         75
                                 ELECTRICAL COMPONENTS
Wastegate Control Solenoid
The PCM provides a duty cycle to the
solenoid which changes the vacuum
flow to the actuator causing the
wastegate to open and allow exhaust
gases to bypass the turbine.
The wastegate helps maintain the
required intake manifold pressure.
It is used when mostly when
intake manifold pressure needs to
be decreased quickly. When the
wastegate is opened, exhaust back
pressure is decreased, reducing the
turbocharger turbine speed.
IDS: TURBO_WGATE (%)
                                           76
                                             EXHAUST SYSTEM
Exhaust gases exit the exhaust ports into the inboard exhaust manifolds and are directed to the dual turbine inlet of the
turbo through the right and left side up-pipes. The exhaust gas and heat spins the turbine wheel inside the turbocharger.
The turbine wheel spins the compressor wheel(s) via their common shaft. Some of the exhaust from the passenger side
manifold is directed to the EGR valve through the EGR inlet pipe. When the EGR valve is being operated, exhaust flow
goes through the valve and is routed through either the EGR cooler or bypasses the cooler. This is done by the EGR
cooler bypass valve. The exhaust gas enters the lower intake manifold and combines with the fresh air.
                                                             77
                                           EXHAUST SYSTEM
Turbocharger Down Pipe
The turbocharger down pipe is double-
walled to help retain heat for the after
treatment system. It connects to the
turbocharger with a V-band clamp
connector.
                                                 78
        EXHAUST SYSTEM
                            Diesel Particulate Filter (DPF)
                            The DPF is a highly engineered silicon
                            carbide wall-flow catalyst that traps
                            particulates, reducing the amount of
                            black smoke emitted from the tailpipe.
                            The three modes of DPF regeneration
                            are active, passive and manual.
               79
                                          EXHAUST SYSTEM
EGT Sensor Operation                                                            Exhaust Gas Temperature (EGT)
The electrical resistance of the                     2.5
sensor increases as the temperature
increases, and resistance decreases
as the temperature decreases.                         2
                                           Voltage
temperature. The PCM uses the input
from four EGT sensors to monitor the                  1
0.5
                                                      0
                                                       -50   150        350   550     750        950        1150   1350   1550   1750
                                                                                      Temperature (Deg F)
Regeneration Process
As soot gathers in the aftertreatment system, the exhaust begins to become restricted. Regeneration is the process in
which soot is burned off from the inside of the DPF. Regeneration is commanded by the PCM.
The PCM starts regeneration of the DPF if the soot load exceeds a calibrated value. The PCM determines the load
condition of the DPF, based on the exhaust gas pressure upstream of the DPF. The DPF pressure sensor provides the
pressure input to the PCM.
This soot can be cleaned by passive, active, or manual regeneration. Manual regeneration is performed by using the IDS.
Passive Regeneration
Passive regeneration takes place when exhaust temperatures exceed 300°C (572°F). This process does not affect engine
performance and is transparent to the driver.
Active Regeneration
Active regeneration occurs when exhaust temperatures are insufficient to achieve passive regeneration and the DPF
pressure sensor is indicating the need for regeneration.
The PCM automatically activates the left bank fuel injectors only during the exhaust stroke to raise exhaust temperature to
begin regeneration while the vehicle is in motion.
Engine performance is not affected by active regeneration, however the engine or exhaust tone may change.
Manual Regeneration
The IDS can be used to perform a manual regeneration of the DPF in the shop and set the ash value under stationary
conditions to clean and calibrate the system. The Malfunction Indicator Lamp (MIL) may illuminate when service or
maintenance of the DPF is necessary.
CAUTION: The manual regeneration of the DPF produces high temperatures in the exhaust system. Due to high exhaust
gas temperatures, always follow the Workshop Manual Cautions, Warnings, and procedures when performing a manual
DPF regeneration.
Frequency of Regeneration
The mileage between regenerations varies significantly, depending on vehicle usage.
Post Regeneration
After regeneration, the PCM reads the pressure at the DPF pressure sensor and compares it with a calibrated value. From
this comparison, the PCM determines the ash quantity inside the DPF.
Non-Burnable Ash
Over time a slight amount of non-burnable ash builds up in the DPF which is not removed during the regeneration
process. Ash comes from the fuel, oils and other materials that remain after the DPF regeneration process. The DPF may
need to be removed for ash cleaning and replaced with a new or remanufactured part.
Handle the DPF with care. Dropping the DPF may cause internal damage.
                                                            81
                                         EXHAUST SYSTEM
Selective Catalyst Reduction (SCR)
The SCR system components include
the:
•	 reductant or Diesel Exhaust Fluid
   (DEF)
•	 reductant tank
•	 reductant dosing module
•	 reductant pump and heater
   assembly
•	 reductant pressure line heater
   assembly
•	 reductant tank heater and sensor
   assembly
•	 reductant purge valve
•	 reductant pressure sensor
•	 NOx sensor and module
•	 exhaust mixing system.
Reductant Tank
The reductant tank stores the
reductant or DEF. Under normal use
it needs to be refilled at the same
interval as the oil change.
                                               82
          EXHAUST SYSTEM
                                 Reductant Dosing Module
                                 The reductant dosing module is
                                 controlled by the PCM. The reductant
                                 dosing module injects reductant
                                 into the exhaust system to reduce
                                 NOx coming out of the tailpipe. The
                                 injector is made to resist the corrosive
                                 properties of the reductant.
                                 Reductant Pump
                Reductant Pump   The reductant pump supplies urea
                                 to the dosing module. One unique
                                 function of the pump is that when the
                                 ignition is turned off, the pump pulls all
                                 of the reductant out of the lines. This
                                 prevents damage to the lines if the
                                 reductant was to freeze.
Tank Heater
                 83
                                            EXHAUST SYSTEM
Reductant Fluid Level Sensors
The reductant fluid level sensor
operates by using four electrodes
(one not visible in the picture) that are
mounted on the sensor at different
levels. The reductant solution closes
the electric circuit between electrodes
for each level interface. The signal is
then converted before being sent to
the PCM.
                                                       Reductant Fluid
                                                        Level Sensors
                                                         Reductant
                                                        Purge Valve
                                                  84
              EXHAUST SYSTEM
                                       NOx Sensor Module
                                       The NOx sensor module is mounted
                                       to the vehicle frame under the body.
                                       It controls the NOx sensor mounted
                                       in the diesel aftertreatment exhaust
                                       system downstream of the SCR and
                                       DPF. It communicates to the PCM
                                       via the CAN2 to report NOx and O2
                                       concentrations as well as sensor and
                                       controller errors.
                                       NOx Sensor
                                       The NOx sensor is used primarily to
                               NOx     sense O2 and NOx concentrations
                              Sensor   in diesel exhaust gas. The sensor is
                                       mounted in a vehicle’s exhaust pipe,
                                       perpendicular to exhaust gas flow. The
                                       sensor is mounted downstream of the
                                       SCR and DPF. The sensor interfaces
                                       with the NOx sensor module that
                                       controls the sensor and heater circuits.
DEF Defuser
                       85
                                            EXHAUST SYSTEM
Selective Catalyst Reduction (SCR) System Operation
The SCR system reduces nitrogen oxides (NOx) present in the exhaust stream to nitrogen (N2) and water (H2O). The SCR
contains a ceramic catalyst washcoated with copper and iron on a zeolite substrate. At the inlet of the SCR catalyst is a
port for the reductant dosing module, followed by a grate diffuser and a twist mixer. When Diesel Exhaust Fluid (DEF) is
introduced into the system, it finely atomizes in the grate diffuser and mixes evenly with exhaust gases in the twist mixer.
During this time, the heat of the exhaust gases causes the urea to split into carbon dioxide (CO2) and ammonia (NH3). As
the ammonia and NOx pass through the ceramic SCR catalyst, a reduction reaction takes place and the ammonia and
NOx are converted to N2 and H2O.
The engine is able to run leaner and therefore more efficiently because of the efficiency of the SCR system eliminating the
high NOx levels that are produced under lean conditions.
Heated Lines
                                                            86
SPECIAL SERVICE TOOLS
                    Front Crank Seal Remover
                    The Front Crank Seal Remover,
                    303-1510 is used to remove the front
                    crankshaft seal.
         87
                                       SPECIAL SERVICE TOOLS
Rear Crank Seal Installer
The Rear Crank Seal Installer,
303-1514 is used to install the rear
crankshaft seal.
                                                 88
SPECIAL SERVICE TOOLS
                    EGR Pressure Tester
                    The EGR Pressure Tester, 303-1511 is
                    used to check for coolant leaks.
                    EGR Cooler Primary Coolant Passage
                    Tester
         89
                                     SPECIAL SERVICE TOOLS
Compression Adapter Tester
The Compression Adapter Tester, 303-
1515 is used to adapt the compression
tester to the 6.7L diesel engine.
90