3.GENERATOR FIELD COIL SHORTED TO GROUND
Measure the resistance between ground and the Generator Field terminals on the Generator.
Istheresistancebelow100ohms?
Ye s>>
Replace or repair the Generator Field Coil for a short to ground.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.BATTERY TEMPERATURE SENSOR
Connect the PCM harness connectors and the Generator harness connector.
Ignition on, engine not running.
With the scan tool in Inputs/Outputs, read the Batt Temp Sensor value.
Using a thermometer measure under hood temperature near Battery tray.
Is the temperature within 10 deg of Battery temperature?
Ye s>>
Go To 5
No>>
Replace the Battery Temperature Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
5.PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.
If there are no possible causes remaining, view repair.
Repair
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.(C918) A/C PRESSURE SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the PCM harness connectors.
Ignition on, engine not running.
Measure the voltage on the (C918) A/C Pressure Signal circuit in the
A/C Pressure Sensor harness connector.
Is the voltage above 5.2 volts?
Ye s>>
Repair the short to voltage in the (C918) A/C Pressure Sig-
nal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(C918) A/C PRESSURE SIGNAL CIRCUIT OPEN
Turn the ignition off.
Measure the resistance of the (C918) A/C Pressure Signal circuit
between the A/C Pressure Sensor harness connector and the PCM har-
ness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 5
No>>
Repair the open in the (C918) A/C Pressure Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
With the ignition key on and the engine running over 1500 RPM after 25 seconds.
Set Condition:
When the PCM regulates the generator field and there are no detected field problems, but the voltage output
does not increase.
Possible Causes
BATTERY TEMPERATURE SENSOR
RESISTANCE IN THE BATTERY POSITIVE CIRCUIT
(K125) GENERATOR FIELD SOURCE CIRCUIT OPEN
RESISTANCE IN THE GENERATOR GROUND
(K125) GENERATOR FIELD SOURCE CIRCUIT SHORTED TO GROUND
(K20) GENERATOR FIELD CONTROL CIRCUIT OPEN
RESISTANCE IN THE GENERATOR FIELD COIL
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.CHARGING VOLTAGE BELOW 15.1 VOLTS
Turn the ignition off.
NOTE: Battery must be fully charged and capable of passing a battery load test.
NOTE: Generator Belt tension and condition must be checked before continuing.
NOTE: Inspect the vehicle for any aftermarket accessories that may exceedthe maximum Generator output.
WARNING: When the engine is operating, do not stand in direct line of the fan. Do not put your hands near
the pulley, belts, or fan. Do no wear loose clothing.
Start the engine.
Record all DTCs and the related Freeze Frame data.
With the scan tool, read the target charging voltage.
Is the target charging voltage above 15.1 volts?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.BATTERY TEMPERATURE SENSOR
Turn the ignition off.
NOTE: Generator Belt tension and condition must be checked before continuing.
Start the engine.
Allow the engine to reach normal operating temperature.
With the scan tool in sensors, read the Battery Temp Sensor value.
Using a Thermometer, measure under hood temperature.
Is the temperature within 10° F of Battery temperature?
Ye s>>
Go To 3
No>>
Replace the Battery Temperature Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.HIGH RESISTANCE IN THE BATTERY POSITIVE CIRCUIT
Ignition on, engine not running.
Measure the voltage between the Generator B+ Terminal and the Battery Positive Post.
WARNING: When the engine is operating, do not stand in direct line of the fan. Do not put your hands near
the pulley, belts, or fan. Do no wear loose clothing.
CAUTION: Make sure all wires are clear of the engine’s moving parts.
Start the engine.
Is the voltage above 0.4 of a volt?
Ye s>>
Repair the excessive resistance in the Battery Positive circuit between the Generator and Battery.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.RESISTANCE IN THE GENERATOR GROUND
Start the engine.
WARNING: When the engine is operating, do not stand in direct line of the fan. Do not put your hands near
the pulley, belts, or fan. Do no wear loose clothing.
Warm the engine to operating temperature.
CAUTION: Make sure all wires are clear of the engine’s moving parts.
Measure the voltage between the Generator case and Battery Negative Post.
Is the voltage above 0.1 of a volt?
Ye s>>
Repair the excessive resistance in the Generator Ground circuit between the Generator Case and Bat-
tery Negative side.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.(K125) GEN FIELD SOURCE CIRCUIT OPEN
Ignition on, engine not running.
Carefully inspect all connectors for corrosion or spread terminals before continuing.
With the scan tool actuate the Generator Field Driver.
While backprobing, measure the voltage on the (K125) Generator Field SourcecircuitatbackofGenerator.
Is the voltage above 10.0 volts?
Ye s>>
Go To 6
No>>
Repair the open in the (K125) Generator Field Source circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts.
Set Condition:
No BUS messages recieved from the BCM for 20 seconds.
Possible Causes
(D25) PCI BUS CIRCUIT OPEN
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.DTC RESET
Ignition on, engine not running.
With the scan tool, erase DTCs.
Cycle the ignition key on and off several times. Leaving the ignition on forat least 20 seconds.
With the scan tool, read DTCs.
Does the DTC reset?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.COMMUNICATE WITH FCM
With the scan tool, attempt to communicate with the FCM.
Can communication be established with the BCM?
Ye s>>
Go To 3
No>>
Refer to the Communication Category and perform the appropriate symptom related to no communica-
tion with FCM.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
P1696-PCM FAILURE EEPROM WRITE DENIED
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Ignition on and battery voltage greater than 10 volts.
Set Condition:
An attempt to program/write to the internal EEPROM failed, also checks at powerdown.
Possible Causes
SRI MILEAGE INVALID
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.SCAN TOOL DISPLAYS WRITE FAILURE
Ignition on, engine not running.
With the scan tool, perform the SRI Memory Test.
Does the scan tool display Write Failure?
Ye s>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.SCAN TOOL DISPLAYS WRITE REFUSED
With the scan tool, perform the SRI Memory Test.
Does the scan tool display Write Refused?
Ye s>>
Go To 3
No>>
Go To 4
3.PCM REFUSED 2ND TEST
With the scan tool, perform the SRI Memory Test a second time.
NOTE: Retest the SRI Memory two more times.
Does the scan tool display Write Refused again?
Ye s>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
4.SCAN TOOL DISPLAYS SRI MILEAGE INVALID
With the scan tool, perform the SRI Memory Test.
Does the scan tool display SRI Mileage Invalid?
Ye s>>
Update the mileage and retest the SRI Memory.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
Possible Causes
GENERATOR BELT CONDITION
RESISTANCE IN THE BATTERY POSITIVE CIRCUIT
(K125) GENERATOR FIELD SOURCE CIRCUIT OPEN
GENERATOR FIELD COIL HIGH RESISTANCE
(K20) GEN FIELD CONTROL CIRCUIT OPEN
RESISTANCE IN THE GENERATOR GROUND
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.TARGET CHARGING DIFFERS FROM ACTUAL CHARGING BY 1 VOLT
NOTE: Verify that the Battery is able to pass a load test before continuing.
Ignition on, engine not running.
With the scan tool, read the Battery voltage and record the results.
Measure Battery voltage between the Battery Positive and Negative Terminals and record the results.
Compare the two voltage readings.
Is the voltage difference less than one volt?
Ye s>>
Go To 2
No>>
Go To 8
2.RESISTANCE IN THE BATTERY POSITIVE CIRCUIT
Ignition on, engine not running.
Measure the voltage between the Generator B+ Terminal and the Battery+ Post.
CAUTION: Make sure all wires are clear of the engine’s moving parts.
Start the engine.
Is the voltage above 0.4 of a volt?
Ye s>>
Repair the excessive resistance in the Battery Positive circuit between the Generator and Battery.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
3.(K125) GEN FIELD SOURCE CIRCUIT OPEN
Ignition on, engine not running.
Record all DTCs and freeze frame data, now erase Codes.
Carefully inspect all connectors for corrosion or spread terminals before continuing.
With the scan tool, actuate the Generator Field Driver.
Measure the voltage of the (K125) Generator Field Source circuit by backprobing the back of Generator Field har-
ness connector.
Is the voltage above 10.0 volts?
Ye s>>
Go To 4
No>>
Repair the (K125) Generator Field Source circuit for an open or short to ground.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
4.RESISTANCE IN THE GENERATOR GROUND
Start the engine.
Warm the engine to operating temperature.
CAUTION: Make sure all wires are clear of the engine’s moving parts.
Measure the voltage between the Generator case and Battery Negative Post.
Is the voltage above 0.1 of a volt?
Ye s>>
Repair the excessive resistance in the Generator Ground circuit between the Generator Case and Bat-
tery Ground side.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
5.GENERATOR FIELD COIL HIGH RESISTANCE
Turn the ignition off.
Disconnect the Generator Field harness connector at back of the Generator.
Measure resistance across the Generator Field Terminals at the Generator.
Is the resistance above 15 ohms?
Ye s>>
Replace or repair the Generator as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
6.(K20) GEN FIELD CONTROL CIRCUIT OPEN
Disconnect the C3 PCM harness connector.
Measure the resistance of the (K20) Generator Field Driver circuit
between the C3 PCM harness connector and the Generator harness
connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 7
No>>
Repair the open in the (K20) Gen Field Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
7.PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.
If there are no possible causes remaining, view repair.
Repair