2012 Ford Pickup 3.

7L Eng VIN M F150

Print Date: 02/10/2019
Description

The Smart Junction Box (SJB) is also identified as the Generic Electronic Module (GEM) or Body
Control Module (BCM).
The PSCM monitors the HS-CAN bus when the ignition has been on for more than 5 seconds,
when the voltage to the PSCM is greater than 6.5 volts and when there are no DTCs present that
are inhibiting PSCM operation.

DTC U0140:00 (Lost Communication with the Body Control Module: No Sub Type
Information) - This DTC sets when communication between the PSCM and the BCM module
fails. The PSCM has not received the alternator signal from the BCM.

Inspection And Verification

NOTE: Under no circumstances should the accessory

drive belt, tensioner or pulleys have any fluids or belt
dressing applied to them as damage to the belt material and
tensioner damping mechanism may occur.

1. Verify the customer concern by operating the system.

2. Visually inspect for obvious signs of mechanical damage.

VISUAL INSPECTION CHART

Mechanical

1. Drive belt cracking/chunking/wear

2. Belt/pulley contamination
3. Incorrect accessory drive belt
4. Incorrectly routed accessory drive belt
5. Pulley misalignment or excessive pulley runout
6. Loose or mislocated hardware
7. Loose accessory drive belt
8. Damaged pulleys
9. Tensioner arm misalignment

Belt Tensioner With Belt Length Indicator - 3.5L and 3.7L

Fig 1: Identifying Belt Tensioner With Belt Length Indicator - 3.5L And 3.7L

Courtesy of FORD MOTOR CO.

Item Description

1 Belt length indicator

 2 Acceptable belt installation and wear range

3 Belt replacement range

4 Belt tension relief point

Belt Tensioner With Belt Length Indicator - 5.0L

Fig 2: Identifying Belt Tensioner With Belt Length Indicator - 5.0L

Courtesy of FORD MOTOR CO.

 Item Description

1 Belt length indicator

2 Acceptable belt installation and wear range

3 Belt replacement range

4 Belt tension relief point

Belt Tensioner With Belt Length Indicator - 6.2L

NOTE: 6.2L (2V) accessory drive belt tensioner shown

in illustration, other accessory drive belt tensioners similar.

NOTE: Belt tensioner is shown in illustration in the

free-state position against the arm travel stops.
Fig 3: Identifying Belt Tensioner With Belt Length Indicator - 6.2L

Courtesy of FORD MOTOR CO.

Item Description

1 Belt length indicator

 2 Acceptable belt installation and wear range

3 Belt replacement range

4 Belt tension relief point

3. Check that the belt length indicator, if equipped, on the belt tensioner is in the acceptable belt
installation and wear range. If the indicator is in the belt replacement range, either an incorrect
belt is installed or the belt is worn beyond the service limit. Install a new belt as necessary.

4. Eliminate all other non-belt related noises that could cause belt misdiagnosis, such as A/C
compressor engagement chirp, A/C slugging noise, power steering cavitations at low
temperatures, Variable Camshaft Timing (VCT) tick or generator whine.

5. If a concern is found, correct the condition before proceeding to the next step.
V-Ribbed Serpentine Drive Belt With Cracks Across Ribs
Fig 4: Identifying V-Ribbed Serpentine Drive Belt Dimension

Courtesy of FORD MOTOR CO.

6. Check the belt for cracks. Up to 15 cracks in a rib over a distance of 100 mm (4.0 in) can be
considered acceptable. If cracks exceed this standard, install a new belt.
V-Ribbed Serpentine Belt With Piling

NOTE: Piling is an excessive buildup in the V-grooves

of the belt.
 Fig 5: Identifying V-Ribbed Serpentine Belt With Piling

Courtesy of FORD MOTOR CO.

7. The condition of the V-ribbed drive belt should be compared against the illustration and
appropriate action taken.

1. Small scattered deposits of rubber material. This is not a concern, therefore, installation of a
new belt is not required.
 2. Longer deposit areas building up to 50% of the rib height. This is not considered a durability
concern, but it can result in excessive noise. If noise is apparent, install a new belt.

3. Heavy deposits building up along the grooves resulting in a possible noise and belt stability
concern. If heavy deposits are apparent, install a new belt.
V-Ribbed Serpentine Belt With Chunks of Rib Missing
Fig 6: Identifying V-Ribbed Serpentine Belt With Chunks Of Rib Missing

Courtesy of FORD MOTOR CO.

8. There should be no chunks missing from the belt ribs. If the belt shows any evidence of this,
install a new accessory drive belt.

9. If the concern is not visually evident, verify the symptom and GO to Symptom Chart.

Normal Operation [ Pinpoint Test C: DTC P0620 ]

The PCM monitors the generator output via the generator monitor (GENMON) circuit. The PCM
uses the generator command (GENCOM) circuit to command the generator to either increase or
decrease output. If the GENCOM circuit (generator control circuit) or the "A" sense circuit are open
or shorted to ground, the PCM will not be able to control the generator output. When the engine
speed is greater than approximately 2, 000 RPM, the generator defaults to a steady voltage output
of approximately 13.5 volts and the PCM sends a request to the Instrument Panel Cluster (IPC) to
illuminate the charging system warning indicator. A GENCOM circuit fault can be confirmed by
viewing the PCM PID generator command line fault (GENCMD_LF) (YES status indicator fault).

DTC P0620 (Generator Control Circuit) - The PCM sets this DTC if the GENCOM circuit or
"A" sense circuit are open or shorted to ground.

This pinpoint test is intended to diagnose the following:

Fuse
Wiring, terminals or connectors
 Radial arm adapter
Generator
PCM

PINPOINT TEST C: DTC P0620

NOTE: Make sure battery voltage is greater than 12.2

volts prior to and during this pinpoint test.

NOTE: Do not have a battery charger attached during

vehicle testing.

C1 CHECK THE BATTERY CONDITION

REFER to BATTERY, MOUNTING AND CABLES and carry out Pinpoint Test A: System
Voltage High Battery Condition Test to determine if the battery can hold a charge and is
OK for use.
Does the battery pass the condition test?
YES : GO to C2.
No : INSTALL a new battery. REFER to BATTERY, MOUNTING AND CABLES .
CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

C2 CHECK THE GENERATOR CONNECTIONS

Ignition OFF.
Inspect generator C102A connection. Connector should be installed correctly and tight.
Disconnect: Generator C102A.
Inspect generator C102A for bent and/or pushed-out pins.
Inspect generator C102B, B+ circuit SDC14 (RD). Connection should be tight.
Measure the battery voltage.
Fig 7: Measuring Battery Voltage

Courtesy of FORD MOTOR CO.

Measure the voltage between generator C102B, B+ circuit SDC14 (RD) and ground.

NOTE: 6.2L shown in illustration, others similar.

 Fig 8: Measuring Voltage Between Generator C102B, B+ Circuit SDC14 (RD) And Ground

Courtesy of FORD MOTOR CO.

Is generator C102B connection tight and does the generator B+ measure battery
voltage?
YES : GO to C3.
No : For 3.5L, 3.7L and 5.0L engines , VERIFY high current BJB 250A fuse is
OK. If OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the Wiring Diagrams
information to identify the possible causes of the circuit short. CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.
For 6.2L engines , VERIFY fusible links are OK. If OK, REPAIR circuit SDC14
(RD). If not OK, REFER to the Wiring Diagrams information to identify the
possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test.
TEST the system for normal operation.

C3 CHECK THE VOLTAGE DROP IN THE B+ CIRCUIT

Connect: Generator C102A.
Start the engine.
With the engine running at idle, headlamps on and blower on high, measure the voltage
drop between generator B+ C102B, circuit SDC14 (RD) and the positive battery terminal.
 Fig 9: Measuring Voltage Drop Between Generator B+ C102B, Circuit SDC14 (RD) And
Positive Battery Terminal

Courtesy of FORD MOTOR CO.

Carry out a wiggle test of the generator wiring and connections while measuring voltage
drop.
Is the voltage drop less than 0.5 volt?
YES : GO to C4.
No : INSPECT circuit SDC14 (RD), radial arm adapter and the positive battery
cable for loose connections, physical damage or wire corrosion. REPAIR as
necessary. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal
operation.

C4 "A" SENSE CIRCUIT LOAD TEST

NOTE: The following step uses a test light to simulate

normal circuit loads. Use only the test light recommended
in the Special Tools table at the beginning of this
information. To avoid connector terminal damage, use the
Flex Probe Kit for the test light probe connection to the
vehicle. Do not use the test light probe directly on any
connector.
 NOTE: This step puts a load on the "A" sense circuit. If
there are corroded or loose connections, loading the circuit
may help show the fault. A 250-350 mA incandescent 12-
volt test lamp is required for this step. This circuit will not be
loaded properly using an LED-style test lamp.

Ignition OFF.
Disconnect: Generator C102A.
Ignition ON.
Using a 12-volt test lamp connected to ground, while performing a wiggle test on the
generator harness, check for voltage at:
For 3.5L, 3.7L and 5.0L engines , generator C102A-3, circuit SBB45 (GY/RD),
harness side.
For 6.2L engines , generator C102A-3, circuit SDC14 (RD), harness side.
Fig 10: Checking For Voltage At Generator C102A-3, Circuit SBB45 (GY/RD), Harness
Side

Courtesy of FORD MOTOR CO.

Does the test lamp illuminate?

YES : GO to C5.
No : For 3.5L, 3.7L and 5.0L engines , VERIFY high current BJB 250A fuse is
OK. If OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the Wiring Diagrams
information to identify the possible causes of the circuit short. CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.
 For 6.2L engines , VERIFY fusible links are OK. If OK, REPAIR circuit SDC14
(RD). If not OK, REFER to the Wiring Diagrams information to identify the
possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test.
TEST the system for normal operation.

C5 CHECK THE GENERATOR COMMAND LINE FAULT (GENCMD_LF) PID

Ignition OFF.
Connect: Generator C102A.
Start the engine.
Select and monitor the following PCM PIDs:

NOTE: Many of the PCM PIDs selected will be

monitored later in this pinpoint test.

Generator Monitor (GENMON)

Generator Command (GENCMD)
Generator Command Line Fault (GENCMD_LF)
With the engine running at idle, monitor the GENCMD_LF PID.
Does the GENMON_LF PID indicate FAULT?
YES : GO to C6.
No : GO to C9.

C6 CHECK THE GENERATOR COMMAND CIRCUIT FOR A SHORT TO POWER

Ignition OFF.
Disconnect: Generator C102A.
Ignition ON.
Measure the voltage between generator C102A-2, circuit CDC10 (BU/OG), harness side
and ground.
 Fig 11: Measuring Voltage Between Generator C102A-2, Circuit CDC10 (BU/OG) And
Ground

Courtesy of FORD MOTOR CO.

Does voltage read 1 volt or less?

YES : GO to C7.
No : GO to C11.

C7 COMPARE THE PCM PIDs GENERATOR MONITOR (GENMON) AND GENERATOR

COMMAND (GENCMD)
Ignition OFF.
Connect a fused jumper wire between generator C102A-1, circuit CDC15 (VT), harness
side and generator C102A-2, circuit CDC10 (BU/OG), harness side.
 Fig 12: Connecting Fused Jumper Wire Between Generator C102A-1, Circuit CDC15 (VT)
And Generator C102A-2, Circuit CDC10 (BU/OG)

Courtesy of FORD MOTOR CO.

Start the engine.

Monitor the GENMON and GENCMD PIDs while performing a wiggle test on the generator
harness.
Does the GENMON PID read within 5% of the GENCMD PID?
YES : GO to C8.
No : GO to C12.

C8 CHECK THE GENERATOR COMMAND CIRCUIT FOR DAMAGE OR AN OPEN

Ignition OFF.
Disconnect: Fused Jumper Wire.
Disconnect: PCM C1551B (3.5L).
Disconnect: PCM C175B (3.7L).
Disconnect: PCM C1381B (5.0L and 6.2L).
Inspect the following harness connectors for damaged or pushed-out pins:
PCM C1551B-59, circuit CDC10 (BU/OG) (3.5L)
PCM C175B-53, circuit CDC10 (BU/OG) (3.7L)
PCM C1381B-53, circuit CDC10 (BU/OG) (5.0L and 6.2L)
 Generator C102A-2, circuit CDC10 (BU/OG)
For 3.5L equipped vehicles , measure the resistance between PCM C1551B-59, circuit
CDC10 (BU/OG), harness side and generator C102A-2, circuit CDC10 (BU/OG), harness
side.
Fig 13: Measuring Resistance Between PCM C1551B-59, Circuit CDC10 (BU/OG) And
Generator C102A-2, Circuit CDC10 (BU/OG)

Courtesy of FORD MOTOR CO.

For 3.7L equipped vehicles , measure the resistance between PCM C175B-53, circuit
CDC10 (BU/OG), harness side and generator C102A-2, circuit CDC10 (BU/OG), harness
side.
Fig 14: Measuring Resistance Between PCM C175B-53, Circuit CDC10 (BU/OG) And
Generator C102A-2, Circuit CDC10 (BU/OG)

Courtesy of FORD MOTOR CO.

For 5.0L and 6.2L equipped vehicles , measure the resistance between PCM C1381B-
53, circuit CDC10 (BU/OG), harness side and generator C102A-2, circuit CDC10
(BU/OG), harness side.
 Fig 15: Measuring Resistance Between PCM C1381B-53, Circuit CDC10 (BU/OG) And
Generator C102A-2, Circuit CDC10 (BU/OG)

Courtesy of FORD MOTOR CO.

Are the connectors and pins free of damage and is the resistance less than 5 ohms?
YES : GO to C9.
No : REPAIR circuit CDC10 (BU/OG). CLEAR the DTCs. REPEAT the self-test.
TEST the system for normal operation.

C9 CHECK THE GENERATOR COMMAND CIRCUIT FOR A SHORT TO GROUND

Ignition OFF.
Disconnect: Generator C102A (if not previously disconnected).
Disconnect: PCM C1551B (3.5L) (if not previously disconnected).
Disconnect: PCM C175B (3.7L) (if not previously disconnected).
Disconnect: PCM C1381B (5.0L and 6.2L) (if not previously disconnected).
Measure the resistance between the generator C102A-2, circuit CDC10 (BU/OG), harness
side and ground.
 Fig 16: Measuring Resistance Between Generator C102A-2, Circuit CDC10 (BU/OG),
Harness Side And Ground

Courtesy of FORD MOTOR CO.

Is the resistance greater than 10, 000 ohms?

YES : GO to C10.
No : REPAIR circuit CDC10 (BU/OG). CLEAR the DTCs. REPEAT the self-test.
TEST the system for normal operation.

C10 CHECK THE CHARGING SYSTEM CIRCUITS FOR INTERMITTENT FAULTS

Connect: Generator C102A.
Connect: PCM C1551B (3.5L).
Connect: PCM C175B (3.7L).
Connect: PCM C1381B (5.0L and 6.2L).
Ignition ON.
Clear all DTCs.
Start the engine and let the engine run for 5 minutes.
Retrieve Continuous Memory Diagnostic Trouble Codes (CMDTCs) from all modules.
Did any charging system DTC get stored into memory?
YES : INSTALL a new generator. REFER to Generator - 3.5L GTDI, Generator -
3.7L, Generator - 5.0L or Generator - 6.2L . CLEAR the DTCs. REPEAT the self-
test. TEST the system for normal operation.
No : The fault is not present at this time. This may indicate an intermittent fault.
CARRY OUT a wiggle test on the charging system circuits to try and RECREATE
the concern. CHECK generator connections for corrosion, loose connections
 and/or bent terminals. REPAIR as necessary. CLEAR the DTCs. REPEAT the
self-test. TEST the system for normal operation.

C11 CHECK GENERATOR COMMAND CIRCUIT FOR SHORT TO VOLTAGE

Ignition OFF.
Disconnect: Generator C102A.
Disconnect: PCM C1551B (3.5L).
Disconnect: PCM C175B (3.7L).
Disconnect: PCM C1381B (5.0L and 6.2L).
Ignition ON.
Measure the voltage between generator C102A-2, circuit CDC10 (BU/OG), harness side
and ground.
Fig 17: Measuring Voltage Between Generator C102A-2, Circuit CDC10 (BU/OG),
Harness Side And Ground

Courtesy of FORD MOTOR CO.

Is any voltage present?

YES : REPAIR circuit CDC10 (BU/OG). CLEAR the DTCs. REPEAT the self-test.
TEST the system for normal operation.
No : GO to C12.

C12 INSPECT GENERATOR CONNECTORS AND CIRCUITS

Ignition OFF.
Disconnect: PCM C1551B (3.5L).
Disconnect: PCM C175B (3.7L).
 Disconnect: PCM C1381B (5.0L and 6.2L).
Inspect the following connector pins for damage and/or corrosion:
PCM C1551B-96, circuit GD113 (BK/YE) (3.5L)
PCM C1551B-97, circuit GD113 (BK/YE) (3.5L)
PCM C1551B-98, circuit GD113 (BK/YE) (3.5L)
PCM C1551B-99, circuit GD113 (BK/YE) (3.5L)
PCM C175B-50, circuit GD113 (BK/YE) (3.7L)
PCM C175B-69, circuit GD113 (BK/YE) (3.7L)
PCM C175B-70, circuit GD113 (BK/YE) (3.7L)
PCM C1381B-50, circuit GD113 (BK/YE) (5.0L and 6.2L)
PCM C1381B-69, circuit GD113 (BK/YE) (5.0L and 6.2L)
PCM C1381B-70, circuit GD113 (BK/YE) (5.0L and 6.2L)
Generator C102A-1, circuit CDC15 (VT)
Generator C102A-2, circuit CDC10 (BU/OG)
Are the connectors and circuits OK?
YES : GO to C13.
No : REPAIR high resistance or loose connections in the affected circuit(s).
CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

C13 CHECK FOR CORRECT PCM OPERATION

Ignition OFF.
Reinstall BJB fuse 75(20A).
Disconnect all the PCM connectors.
Check for:
corrosion
damaged pins
pushed-out pins
Connect the PCM connectors and make sure they seat correctly.
Operate the system and determine if the concern is still present.
Is the concern still present?
YES : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS .
CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No : The system is operating correctly at this time. The concern may have been
caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-
test.

Normal Operation [ Pinpoint Test D: DTC P0625 Or P0626 ]

The PCM monitors the generator output via the generator monitor (GENMON) circuit (generator
field terminal circuit). If the PCM cannot read the GENMON circuit due to an open or short to
ground, when the engine speed is greater than approximately 2, 000 RPM, the generator defaults
to a steady voltage of approximately 13.5 volts and the PCM sends a request to the Instrument
Panel Cluster (IPC) to illuminate the charging system warning indicator. A GENMON duty cycle of
3% or less indicates a short to ground fault is present and results in DTC P0625 setting in the PCM.
A GENMON duty cycle of 98% or more indicates an open or short to voltage fault is present and
results in DTC P0626 setting in the PCM.

DTC P0625 (Generator Field Terminal Circuit Low) - The PCM sets this DTC if the GENMON
circuit is shorted to ground, the "A" sense circuit is open or the B+ circuit is open. This DTC
also sets by a faulted PCM or generator.
 DTC P0626 (Generator Field Terminal Circuit High) - The PCM sets this DTC if the GENMON
circuit is open or shorted to power. This DTC can also be set by a faulted PCM or generator.

This pinpoint test is intended to diagnose the following:

Fuse
Wiring, terminals or connectors
Radial arm adapter
Engine, generator and battery grounds
Battery
Generator
PCM

PINPOINT TEST D: DTC P0625 OR P0626

NOTE: Make sure battery voltage is greater than 12.2

volts prior to and during this pinpoint test.

NOTE: Do not have a battery charger attached during

vehicle testing.

D1 CHECK THE BATTERY CONDITION

REFER to BATTERY, MOUNTING AND CABLES and carry out Pinpoint Test A: System
Voltage High Battery Condition Test to determine if the battery can hold a charge and is
OK for use.
Does the battery pass the condition test?
YES : GO to D2.
No : INSTALL a new battery. REFER to BATTERY, MOUNTING AND CABLES .
CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

D2 CHECK THE GENERATOR B+ CONNECTION

Ignition OFF.
Inspect generator C102B, circuit SDC14 (RD), harness side. Connection should be tight.
Inspect generator radial adaptor connection on rear of generator. Connection should be
tight.
Measure the voltage between generator C102B, circuit SDC14 (RD) and ground.
 Fig 18: Measuring Voltage Between Generator C102B, Circuit SDC14 (RD) And Ground

Courtesy of FORD MOTOR CO.

Are the generator C102B connections tight and does the generator B+ measure
battery voltage?
YES : GO to D3.
No : For 3.5L, 3.7L and 5.0L engines , TIGHTEN or INSTALL a new C102B (B+
nut) and/or radial arm adapter as needed. REFER to Specifications . VERIFY
high current BJB 250A fuse is OK. If OK, REPAIR circuit SDC14 (RD). If not OK,
REFER to the Wiring Diagrams information to identify the possible causes of the
circuit short. CLEAR the DTCs. REPEAT the self-test. TEST the system for
normal operation.
For 6.2L engines , TIGHTEN or INSTALL a new C102B (B+ nut) and/or radial
arm adapter as needed. REFER to Specifications . VERIFY the fusible link is OK.
If the fusible link is OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the
Wiring Diagrams information to identify the possible causes of the circuit short.
CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

D3 CHECK THE VOLTAGE DROP IN THE B+ CIRCUIT

Start the engine.
With the engine running at idle, headlamps on and blower on high, measure the voltage
drop between generator B+ C102B, circuit SDC14 (RD) and the positive battery terminal.
 Fig 19: Measuring Voltage Drop Between Generator B+ C102B, Circuit SDC14 (RD) And
Positive Battery Terminal

Courtesy of FORD MOTOR CO.

Carry out a wiggle test of the generator wiring and connections while measuring voltage
drop.
Is the voltage drop less than 0.5 volt?
Yes : For DTC P0625 , GO to D4.
For DTC P0626 , GO to D6.
No : INSPECT circuit SDC14 (RD), radial arm adapter and the positive battery
cable for loose connections, physical damage or wire corrosion. REPAIR as
necessary. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal
operation.

D4 "A" SENSE CIRCUIT LOAD TEST

NOTE: The following step uses a test light to simulate

normal circuit loads. Use only the test light recommended
in the Special Tools table at the beginning of this
information. To avoid connector terminal damage, use the
Flex Probe Kit for the test light probe connection to the
vehicle. Do not use the test light probe directly on any
connector.
 NOTE: This step puts a load on the "A" sense circuit. If
there are corroded or loose connections, loading the circuit
may help show the fault. A 250-350 mA incandescent 12-
volt test lamp is required for this step. This circuit will not be
loaded properly using an LED-style test lamp.

Ignition OFF.
Disconnect: Generator C102A.
Ignition ON.
Using a 12-volt test lamp connected to ground, while performing a wiggle test on the
generator harness, check for voltage at:
For 3.5L, 3.7L and 5.0L engines , generator C102A-3, circuit SBB45 (GY/RD),
harness side.
For 6.2L engines , generator C102A-3, circuit SDC14 (RD), harness side.
Fig 20: Checking For Voltage At Generator C102A-3, Circuit SBB45 (GY/RD), Harness
Side

Courtesy of FORD MOTOR CO.

Does the test lamp illuminate?

YES : GO to D5.
No : For 3.5L, 3.7L and 5.0L engines , VERIFY high current BJB 250A fuse is
OK. If OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the Wiring Diagrams
information to identify the possible causes of the circuit short. CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.
 For 6.2L engines , VERIFY fusible links are OK. If OK, REPAIR circuit SDC14
(RD). If not OK, REFER to the Wiring Diagrams information to identify the
possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test.
TEST the system for normal operation.

D5 CHECK GENMON CIRCUIT FOR DAMAGE OR A SHORT TO GROUND

Ignition OFF.
Disconnect: PCM C1551B (3.5L).
Disconnect: PCM C175B (3.7L).
Disconnect: PCM C1381B (5.0L and 6.2L).
Inspect the following harness connectors for damaged or pushed-out pins:
PCM C1551B-26, circuit CDC15 (VT) (3.5L)
PCM C175B-14, circuit CDC15 (VT) (3.7L)
PCM C1381B-14, circuit CDC15 (VT) (5.0L and 6.2L)
Generator C102A-1, circuit CDC15 (VT)
Measure the resistance between generator C102A-1, circuit CDC15 (VT), harness side
and ground.
Fig 21: Measuring Resistance Between Generator C102A-1, Circuit CDC15 (VT), Harness
Side And Ground

Courtesy of FORD MOTOR CO.

Are the connectors and pins free of damage and is the resistance greater than 10,
000 ohms?
YES : GO to D10.
No : REPAIR the connector(s) and/or circuit CDC15 (VT). CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.
D6 CHECK THE GENERATOR B+ RESISTANCE
Ignition OFF.
Disconnect the battery. REFER to BATTERY, MOUNTING AND CABLES .

NOTE: Failure to disconnect the battery will result

in false resistance readings.

Disconnect: Generator C102B.

Measure the resistance between generator C102B, component side and the generator
housing.
Fig 22: Measuring Resistance Between Generator C102B, Component Side And
Generator Housing

Courtesy of FORD MOTOR CO.

Is the resistance greater than 25K ohms?

YES : GO to D7.
No : INSTALL a new generator. REFER to Generator - 3.5L GTDI, Generator -
3.7L, Generator - 5.0L or Generator - 6.2L . CLEAR the DTCs. REPEAT the self-
test. TEST the system for normal operation.

D7 CHECK THE RESISTANCE OF THE VOLTAGE REGULATOR INTERNAL CIRCUITS TO

GROUND
Disconnect: Generator C102A.
Measure the resistance between generator C102A, component side and ground. Refer to
the following table.
 Pin Expected Resistance

1 Greater than 10K ohms

2 Greater than 10K ohms

3 Greater than 10K ohms

Are the resistance values as indicated?

YES : GO to D8.
No : INSTALL a new generator. REFER to Generator - 3.5L GTDI, Generator -
3.7L, Generator - 5.0L or Generator - 6.2L . CLEAR the DTCs. REPEAT the self-
test. TEST the system for normal operation.

D8 CHECK THE GENMON CIRCUIT FOR DAMAGE OR AN OPEN

Disconnect: PCM C1551B (3.5L).
Disconnect: PCM C175B (3.7L).
Disconnect: PCM C1381B (5.0L and 6.2L).
Inspect the following harness connectors for damaged or pushed-out pins:
PCM C1551B-26, circuit CDC15 (VT) (3.5L)
PCM C175B-14, circuit CDC15 (VT) (3.7L)
PCM C1381B-14, circuit CDC15 (VT) (5.0L and 6.2L)
Generator C102A-1, circuit CDC15 (VT)
For 3.5L equipped vehicles , measure the resistance between PCM C1551B-26, circuit
CDC15 (VT), harness side and generator C102A-1, circuit CDC15 (VT), harness side.
Fig 23: Measuring Resistance Between PCM C1551B-26, Circuit CDC15 (VT) And
Generator C102A-1, Circuit CDC15 (VT)

Courtesy of FORD MOTOR CO.

For 3.7L equipped vehicles , measure the resistance between PCM C175B-14, circuit
CDC15 (VT), harness side and generator C102A-1, circuit CDC15 (VT), harness side.
Fig 24: Measuring Resistance Between PCM C175B-14, Circuit CDC15 (VT) And
Generator C102A-1, Circuit CDC15 (VT)

Courtesy of FORD MOTOR CO.

For 5.0L an 6.2L equipped vehicles , measure the resistance between PCM C1381B-14,
circuit CDC15 (VT), harness side and generator C102A-1, circuit CDC15 (VT), harness
side.
 Fig 25: Measuring Resistance Between PCM C1381B-14, Circuit CDC15 (VT) And
Generator C102A-1, Circuit CDC15 (VT)

Courtesy of FORD MOTOR CO.

Are the connectors and pins free of damage and is the resistance less than 5 ohms?
YES : GO to D9.
No : REPAIR the connector(s) and/or circuit CDC15 (VT). CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.

D9 CHECK THE GENMON CIRCUIT FOR A SHORT TO POWER

Connect the battery. REFER to BATTERY, MOUNTING AND CABLES .
Ignition ON.
Measure the voltage between generator C102A-1, circuit CDC15 (VT), harness side and
ground.
 Fig 26: Measuring Voltage Between Generator C102A-1, Circuit CDC15 (VT), Harness
Side And Ground

Courtesy of FORD MOTOR CO.

Is there any voltage present?

YES : REPAIR the connector(s) and/or circuit CDC15 (VT). CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.
No : GO to D10.

D10 COMPARE THE PCM PIDs GENERATOR MONITOR (GENMON) AND GENERATOR
COMMAND (GENCMD)
Ignition OFF.
Connect: PCM C1551B (3.5L).
Connect: PCM C175B (3.7L).
Connect: PCM C1381B (5.0L and 6.2L).
Connect a fused jumper wire between generator C102A-1, circuit CDC15 (VT), harness
side and generator C102A-2, circuit CDC10 (BU/OG), harness side.
 Fig 27: Connecting Fused Jumper Wire Between Generator C102A-1, Circuit CDC15 (VT)
And Generator C102A-2, Circuit CDC10 (BU/OG)

Courtesy of FORD MOTOR CO.

Start the engine.

Using the active command, set the GENVDSD PID to 14.0 volts.
Monitor the GENMON and GENCMD PIDs while carrying out a wiggle test on the
generator wiring harness.
Does the GENMON PID read within 2% of the GENCMD PID?
YES : INSTALL a new generator. REFER to Generator - 3.5L GTDI, Generator -
3.7L, Generator - 5.0L or Generator - 6.2L . CLEAR the DTCs. REPEAT the self-
test. TEST the system for normal operation.
No : GO to D11.

D11 CHECK FOR CORRECT PCM OPERATION

Ignition OFF.
Disconnect all the PCM connectors.
Check for:
corrosion
damaged pins
pushed-out pins
 Connect the PCM connectors and make sure they seat correctly.
Operate the system and determine if the concern is still present.
Is the concern still present?
YES : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS .
TEST the system for normal operation.
No : The system is operating correctly at this time. The concern may have been
caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-
test.

Normal Operation [ Pinpoint Test E: DTC P065B ]

With the engine running, the PCM monitors and expects to receive a valid generator monitor
(GENMON) signal with a duty cycle greater than 5% and less than 98%. The PCM also monitors
the state of the generator command (GENCMD) signal line to make sure it is not stuck high or stuck
low. A DTC sets if the GENMON or GENCMD signal fluctuates between out-of-valid range, stuck
high, stuck low, or some combination and normal. When the engine speed is greater than
approximately 2, 000 RPM, the generator defaults to a steady voltage of approximately 13.5 volts
and the PCM sends a request to the Instrument Panel Cluster (IPC) to illuminate the charging
system warning indicator lamp.

DTC P065B (Generator Control Circuit Range/Performance) - The PCM sets this DTC if the
input frequency was continuously less than 80 Hz or more than 200 Hz. Additionally, if the
signal shows a faulted condition that is happening in a fluctuating manner, the PCM tracks the
fluctuations between faulted and normal conditions. This DTC can also set if the fluctuations
occur frequently within a short amount of time.

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connectors

Radial arm adapter
Generator
PCM

PINPOINT TEST E: DTC P065B

NOTE: Make sure battery voltage is greater than 12.2

volts prior to carrying out this pinpoint test.

NOTE: Do not have a battery charger attached during

vehicle testing.

E1 CHECK THE BATTERY CONDITION

REFER to BATTERY, MOUNTING AND CABLES and carry out Pinpoint Test A: System
Voltage High Battery Condition Test to determine if the battery can hold a charge and is
OK for use.
Does the battery pass the condition test?
YES : GO to E2.
 No : INSTALL a new battery. REFER to BATTERY, MOUNTING AND CABLES .
CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

E2 CHECK THE GENERATOR CONNECTIONS

Ignition OFF.
Inspect generator C102A connection. Connector should be installed correctly and tight.
Disconnect: Generator C102A.
Inspect generator C102A for bent and/or pushed-out pins.
Inspect generator C102B, B+ circuit SDC14 (RD). Connection should be tight.
Measure the battery voltage.
Fig 28: Measuring Battery Voltage

Courtesy of FORD MOTOR CO.

Measure the voltage between generator C102B, B+ circuit SDC14 (RD) and ground.

NOTE: 6.2L shown in illustration, others similar.

 Fig 29: Measuring Voltage Between Generator C102B, B+ Circuit SDC14 (RD) And
Ground

Courtesy of FORD MOTOR CO.

Is generator C102B connection tight and does the generator B+ measure battery
voltage?
YES : GO to E3.
No : For 3.5L, 3.7L and 5.0L engines , TIGHTEN or INSTALL a new C102B (B+
nut) and/or radial arm adapter as needed. REFER to Specifications . VERIFY
high current BJB 250A fuse is OK. If OK, REPAIR circuit SDC14 (RD). If not OK,
REFER to the Wiring Diagrams information to identify the possible causes of the
circuit short. CLEAR the DTCs. REPEAT the self-test. TEST the system for
normal operation.
For 6.2L engines , TIGHTEN or INSTALL a new C102B (B+ nut) and/or radial
arm adapter as needed. REFER to Specifications . VERIFY the fusible link is OK.
If the fusible link is OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the
Wiring Diagrams information to identify the possible causes of the circuit short.
CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

E3 "A" SENSE CIRCUIT LOAD TEST

NOTE: The following step uses a test light to simulate

normal circuit loads. Use only the test light recommended
in the Special Tools table at the beginning of this
information. To avoid connector terminal damage, use the
Flex Probe Kit for the test light probe connection to the
vehicle. Do not use the test light probe directly on any
connector.

NOTE: This step puts a load on the "A" sense circuit. If

there are corroded or loose connections, loading the circuit
may help show the fault. A 250-350 mA incandescent 12-
volt test lamp is required for this step. This circuit will not be
loaded properly using an LED-style test lamp.

Ignition ON.
Using a 12-volt test lamp connected to ground, while performing a wiggle test on the
generator harness, check for voltage at:
For 3.5L, 3.7L and 5.0L engines , generator C102A-3, circuit SBB45 (GY/RD),
harness side.
For 6.2L engines , generator C102A-3, circuit SDC14 (RD), harness side.
Fig 30: Checking For Voltage At Generator C102A-3, Circuit SBB45 (GY/RD), Harness
Side

Courtesy of FORD MOTOR CO.

Does the test lamp illuminate?

YES : GO to E4.
 No : For 3.5L, 3.7L and 5.0L engines , VERIFY high current BJB 250A fuse is
OK. If OK, REPAIR circuit SDC14 (RD). If not OK, REFER to the Wiring Diagrams
information to identify the possible causes of the circuit short. CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.
For 6.2L engines , VERIFY fusible links are OK. If OK, REPAIR circuit SDC14
(RD). If not OK, REFER to the Wiring Diagrams information to identify the
possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test.
TEST the system for normal operation.

E4 CHECK THE PCM GENERATOR MONITOR FREQUENCY (GENMON_HZ) PID

Ignition OFF.
Connect: Generator C102A.
Start the engine.
Select and monitor the following PCM PIDs:

NOTE: Many of the PCM PIDs selected will be

monitored later in this pinpoint test.

Generator Voltage Desired (GENVDSD)

Generator Monitor Frequency (GENMON_HZ)
Monitor the GENMON_HZ PID.
Does the PID read between 80-200 Hz?
YES : GO to E8.
No : GO to E5.

E5 CHECK THE PCM GENERATOR MONITOR FREQUENCY (GENMON_HZ) PID WITH

GENERATOR C102A DISCONNECTED
Ignition OFF.
Disconnect: Generator C102A.
Start the engine.
Monitor the GENMON_HZ PID.
Does the PID read between 0-2 Hz?
YES : GO to E7.
No : GO to E6.

E6 CHECK GENERATOR CIRCUITRY

NOTE: This pinpoint test step directs testing circuits

using a back-probe method. Use the special back-probe
tool specified in the tool list . Do not force test leads or
other probes into connectors. Adequate care must be
exercised to avoid connector terminal damage while
making sure that good electrical contact is made with the
circuit or terminal. Failure to follow these instructions may
 cause damage to wiring, terminals, or connectors and
subsequent electrical faults.

Ignition OFF.
For 3.5L equipped vehicles , with PCM C175B connected, connect a fused jumper wire
between PCM C1551B-26, circuit CDC15 (VT) and ground by carefully back probing the
connector.
For 3.7L equipped vehicles , with PCM C175B connected, connect a fused jumper wire
between PCM C175B-14, circuit CDC15 (VT) and ground by carefully back probing the
connector.
For 5.0L and 6.2L equipped vehicles , with PCM C1381B connected, connect a fused
jumper wire between PCM C1381B-14, circuit CDC15 (VT) and ground by carefully back
probing the connector.
Start the engine.
Monitor the GENMON_HZ PID.
Does the PID read 0 Hz?
YES : INSPECT the harness for wire to wire shorts or insulation chaffing, mis-
pinned connectors and correct wire colors and REPAIR generator circuit CDC15
(VT) as needed. CLEAR the DTCs. REPEAT the self-test. TEST the system for
normal operation.
No : GO to E9.

E7 MONITOR THE PCM PID GENERATOR MONITOR FREQUENCY (GENMON_HZ) WHILE

ACTIVATING THE GENERATOR VOLTAGE DESIRED (GENVDSD) PID
Ignition OFF.
Connect a fused jumper wire between generator C102A-1, circuit CDC15 (VT), harness
side and generator C102A-2, circuit CDC10 (BU/OG), harness side.
 Fig 31: Connecting Fused Jumper Wire Between Generator C102A-1, Circuit CDC15 (VT)
And Generator C102A-2, Circuit CDC10 (BU/OG)

Courtesy of FORD MOTOR CO.

Start the engine.

With the engine running at idle, set the active command GENVDSD PID to 14 volts.
Monitor the GENMON_HZ PID while performing a wiggle test on the generator harness.
Does the GENMON_HZ PID read between 120-130 Hz?
YES : INSTALL a new generator. REFER to Generator - 3.5L GTDI, Generator -
3.7L, Generator - 5.0L or Generator - 6.2L . CLEAR the DTCs. REPEAT the self-
test. TEST the system for normal operation.
No : GO to E9.

E8 CHECK THE PCM GENERATOR COMMAND LINE FAULT (GENCMD_LF) PID

With the engine running and all selectable loads OFF, monitor the PCM PID GENCMD_LF.
Does the PCM PID GENCMD_LF fluctuate from YES FAULT to NO FAULT?
YES : INSTALL a new generator. REFER to Generator - 3.5L GTDI, Generator -
3.7L, Generator - 5.0L or Generator - 6.2L . CLEAR the DTCs. REPEAT the self-
test. TEST the system for normal operation.
No : The fault is not present at this time. This may indicate an intermittent fault.
CARRY OUT a wiggle test on the charging system circuits to try and RECREATE
 the concern. CHECK generator connections for corrosion, loose connections
and/or bent terminals. REPAIR as necessary. CLEAR the DTCs. REPEAT the
self-test. TEST the system for normal operation.

E9 CHECK FOR CORRECT PCM OPERATION

Ignition OFF.
Disconnect all the PCM connectors.
Check for:
corrosion
damaged pins
pushed-out pins
Connect the PCM connectors and make sure they seat correctly.
Operate the system and determine if the concern is still present.
Is the concern still present?
YES : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS .
TEST the system for normal operation.
No : The system is operating correctly at this time. The concern may have been
caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-
test.

Symptom Chart

SYMPTOM CHART

Condition Possible Sources Action

Fuse
Wiring, terminals
or connectors
Engine,
System
generator and GO to Pinpoint Test A.
voltage high
battery grounds
Battery
Generator
PCM

System Fuse GO to Pinpoint Test B.

voltage low Fusible link
or battery is Wiring, terminals
discharged or connectors
Engine,
generator and
battery grounds
Abnormal
ignition-off
current drain(s)
Radial arm
adapter
 Battery
Generator
PCM

Front End
Accessory Drive
The
(FEAD) belt
generator is GO to Pinpoint Test F.
Loose
noisy
bolts/brackets
Generator/pulleys

Generator
Wiring, terminals
Radio or connectors
GO to Pinpoint Test G.
interference In-vehicle
entertainment
system

RETRIEVE Continuous Memory Diagnostic

Charging Wiring, terminals
Trouble Codes (CMDTCs) from all modules. If
system or connectors
any charging system DTCs are found, REFER to
warning Instrument Panel
the Diagnostic Trouble Code (DTC) Chart . If no
indicator is Cluster (IPC)
charging system DTCs are found, REFER to
never/always Generator
INSTRUMENTATION, MESSAGE CENTER,
on PCM
AND WARNING CHIMES .

Charging System

The PCM-controlled, or Smart Charge charging system determines the optimal voltage setpoint for
the charging system and communicates this information to the voltage regulator. The Smart Charge
charging system is designed to set 1 of 6 DTCs any time a charging system fault is present. All of
the DTCs can set continuous faults, but not all DTCs set as on-demand faults.

DTC KOEO KOER Continuous

P0562 X X X

P0563 X (1) X (1)

P0620 X

P0625 X X

P0626 X X

P065B X

(1) Requires vehicle speed above 5 mph.

This system uses 2 communication lines between the PCM and the generator/voltage regulator.
Both of these communication lines use Pulse-Width Modulation (PWM). The generator
communication (GENCOM) line communicates the desired setpoint from the PCM to the voltage
regulator. The generator monitor (GENMON) line communicates the generator load and error
conditions to the PCM. The GENCOM command is only sent by the PCM when it is necessary to
adjust the voltage setpoint. If the setpoint does not need to be changed, several seconds may
elapse between PCM GENCOM commands. This normal operation appears in the PID as
occasional bursts of pulse-width commands. The third pin on the voltage regulator, the "A" pin, is a
circuit dedicated to monitor or sense battery voltage.
The PCM simultaneously controls and monitors the output of the generator. When the current
consumption is high or the battery is discharged, the PCM raises engine speed as needed to
increase generator output. The generator charges the battery and at the same time supplies power
for all of the electrical loads that are required. The battery is more effectively charged with a higher
voltage when the battery is cold and a lower voltage when the battery is warm. The PCM is able to
adjust the charging voltage according to the battery temperature, calculated by using a signal from
the Intake Air Temperature (IAT) sensor. The PCM also uses other inputs to control charging
system voltage such as the Vehicle Speed Sensor (VSS) and Engine Coolant Temperature (ECT).
The voltage setpoint is calculated by the PCM and communicated to the voltage regulator by the
GENCOM circuit based on the needs of the vehicle and the conditions.
The PCM turns off the generator during cranking to reduce the generator load and improve
cranking speed. Once the engine starts, the PCM slowly increases generator output to the desired
voltage.
The PCM reports any charging system faults and sends a message through High Speed Controller
Area Network (HS-CAN) to the Body Control Module (BCM). The BCM controls the charging
system warning indicator by sending a message over the Medium Speed Controller Area Network
(MS-CAN) to the Instrument Panel Cluster (IPC). The IPC then controls charging system warning
indication based on the message from the PCM through the BCM. The status of the PCM charging
system warning indicator and/or message can be confirmed by viewing PCM PID generator fault
indicator lamp (GENFIL). Any charging system fault detected by the PCM results in 1 or more
DTCs being set and the PID GENFIL having a status of On. If equipped with a charging system
warning indicator, the IPC turns the indicator on or off. If equipped with a message center, the IPC
displays a CHECK CHARGING SYSTEM message. When the ignition is ON and the engine is off
on vehicles equipped with a message center, the CHECK CHARGING SYSTEM message may not
be displayed. For information regarding the IPC and message center, REFER to
INSTRUMENTATION, MESSAGE CENTER, AND WARNING CHIMES .
Under certain circumstances, the charging system may have a concern, but still keeps the battery
charged and the vehicle running. GENCOM is normally used to initiate charging, but the generator
may charge with a fault in this circuit. If the engine operates at more than 2, 000 RPM momentarily,
the generator may self-excite or start charging on its own. The charging system warning indicator is
illuminated and/or CHECK CHARGING SYSTEM message is displayed, and the generator
operates in a default mode (approximately 13.5 volts) until the engine is turned off. When the
engine is restarted and the engine operates at more than 2, 000 RPM momentarily, the generator
may again self-excite and again the charging system warning indicator is illuminated and/or
CHECK CHARGING SYSTEM message is displayed.
The PIDs and their associated descriptions used in the charging system diagnosis are listed below:
PID CHART

PID Description Normal Display Associated Connector,

Circuit Name Circuit
 Generator
Generator Constant fluctuating percentage C102A-1,
GENMON monitor
Monitor 3%-98% CDC15 (VT)
(GENMON)

Generator C102A-2,
Generator Fluctuating percentage or small
GENCMD communication CDC10
Command intermittent bursts 3%-98%
(GENCOM) (BU/OG)

Generator Voltage varies by vehicle needs -

GENVDSD Voltage May be controlled by an output - -
Desired state control

Generator
GENFIL Fault Indicator OFF if charging system is OK - -
Lamp

Generator
NO FAULT if GENCOM circuit
GENCMD_LF Command - -
(GENCMD PID) is OK
Line Fault

Generator
GENMON_HZ Monitor Frequency value - -
Frequency

Module
VPWR Supply Within 0.5 volt of battery voltage - -
Voltage

Engine
Engine RPM - May be controlled by
RPM Revolutions - -
an output state control
Per Minute

Battery Drain Test

WARNING: Batteries contain sulfuric acid and produce

explosive gases. Work in a well-ventilated area. Do not allow
the battery to come in contact with flames, sparks or burning
substances. Avoid contact with skin, eyes or clothing. Shield
eyes when working near the battery to protect against
possible splashing of acid solution. In case of acid contact with
skin or eyes, flush immediately with water for a minimum of
15 minutes, then get prompt medical attention. If acid is
swallowed, call a physician immediately. Failure to follow
these instructions may result in serious personal injury.
 NOTE: No factory-equipped vehicle should have more
than a 50 mA (0.050 amp) draw.

NOTE: Many electronic modules draw 10 mA (0.010

amp) or more continuously.

NOTE: Typically, a drain of approximately 1 amp is

attributed to an engine compartment lamp, glove
compartment lamp or interior lamp staying on continually.
Other component failures or wiring shorts are located by
selectively pulling fuses to pinpoint the location of the current
drain. When the current drain is found, the meter reading falls
to an acceptable level. If the drain is still not located after
checking all the fuses, it may be due to the generator.
Disconnect the generator and retest.

NOTE: To accurately test the drain on a battery, an in-

line ammeter must be used between the negative battery
post and its respective cable. Use of a test lamp or voltmeter
is not an accurate method.

1. Make sure the junction box(es)/fuse panel(s) is accessible without turning on the interior lights
or the underhood lights.

2. Drive the vehicle at least 5 minutes and over 48 km/h (30 mph) to turn on and activate the
vehicle systems.

3. Allow the vehicle to sit with the key out of the ignition for at least 40 minutes to allow the
modules to time out/power down.

4. Connect a fused jumper wire (30A) between the negative battery cable and the negative battery
post to prevent modules from resetting.

5. Disconnect the negative battery cable from the negative battery post without breaking the
connection of the jumper wire.

6. Connect the battery tester between the negative battery cable and the post. The meter must be
capable of reading milliamps and should have a 10-amp capability.
 NOTE: To prevent damage to the meter, do not crank
the engine or operate accessories that draw more than
10A.

NOTE: It is very important that continuity is not broken

between the battery and the negative battery cable when
connecting the meter. If this happens, the entire 40-minute
procedure must be repeated.

7. Remove the jumper wire.

NOTE: If the meter settings need to be switched or

the test leads need to be moved to another jack, the
jumper wire must be reinstalled to avoid breaking
continuity.

8. Note the amperage draw. Draw varies from vehicle to vehicle depending on the equipment
package. Compare to a similar vehicle for reference.

NOTE: If the vehicle sits for an extended period of time

and the battery drains, there is the possibility of a control
module staying alive and not going into sleep mode. If a
module does stay alive, it can also result in battery drain. If
a module is suspect, isolate individual modules by
disconnecting each module one at a time and note if the
excessive draw goes away.

NOTE: For vehicles equipped with aftermarket bodies

or boxes which contain electrical connections, disconnect
the aftermarket to factory connections to isolate the body
from the chassis.

9. If the current draw is excessive, remove the fuses from the Battery Junction Box (BJB) one at a
time and note the current drop. When the current level drops to an acceptable level after
 removing a fuse, the circuit containing the excessive draw has been located. The excessive
draw can be isolated by continuing to pull sub system fuses. Do not reinstall the fuses until
testing is finished. To correctly isolate each of the circuits, all of the fuses may need to be
removed, then install one fuse and note the amperage draw, remove the fuse and install the
next fuse. Continue this process with each fuse.
1. Once the main circuit is identified, continue to remove the fuses from the Smart Junction
Box (SJB) one at a time and note the current reading. Do not reinstall the fuses until
testing is finished. To correctly isolate each of the circuits, all of the fuses may need to be
removed, then install one fuse and note the amperage draw, remove the fuse and install
the next fuse. Continue this process with each fuse.

10. Check the wiring diagrams for any circuits that run from the battery without passing through the
BJB or the SJB. If the current draw is still excessive, disconnect these circuits until the draw is
found. Also, disconnect the generator electrical connections and retest if the draw cannot be
located. The generator may be internally shorted, causing the current drain.

Pinpoint Test F: The Generator Is Noisy

Refer to OEM WIRING DIAGRAMS Charging System for schematic and connector information.

Normal Operation

The generator is belt-driven by the engine accessory drive system. There are several sources of
generator noise which include bearing noise, electrical fault noise, generator or belt pulley
misalignment. A generator with certain types of diode or stator failures may also produce an audible
noise.
This pinpoint test is intended to diagnose the following:

Front End Accessory Drive (FEAD) belt

Loose bolts/brackets
Generator/pulley

PINPOINT TEST F: THE GENERATOR IS NOISY

F1 CHECK FOR ACCESSORY DRIVE BELT NOISE AND LOOSE MOUNTING BRACKETS
Ignition OFF.
Check the accessory drive belt and tensioner for damage and correct installation. REFER
to ACCESSORY DRIVE .
Check the accessory mounting brackets and generator pulley for looseness or
misalignment.
Is the accessory drive OK?
YES : GO to F2.
No : REPAIR as necessary. REFER to ACCESSORY DRIVE for diagnosis and
testing of the accessory drive system. TEST the system for normal operation.

F2 CHECK THE GENERATOR MOUNTING

Check the generator mounting for loose bolts or misalignment.
Is the generator mounted correctly?
YES : GO to F3.
No : REPAIR as necessary. TEST the system for normal operation.

F3 CHECK THE GENERATOR FOR NOISE

With the engine running, use a stethoscope or equivalent listening device to probe the
generator and the accessory drive area for unusual mechanical noise.
Is the generator the noise source?
YES : INSTALL a new generator. REFER to Generator - 3.5L GTDI, Generator -
3.7L, Generator - 5.0L or Generator - 6.2L .
No : REFER to ENGINE SYSTEM - GENERAL INFORMATION to diagnose the
source of the engine noise.