When Monitored:
With the ignition on and battery voltage above 10.4 volts.
Set Condition:
An open or shorted condition is detected in the Fuel Pump Relay Control circuit.
Possible Causes
FUEL PUMP RELAY OPERATION
FUEL PUMP RELAY
FUSED IGNITION SWITCH OUTPUT CIRCUIT
(K31) FUEL PUMP RELAY CONTROL CIRCUIT OPEN
(K31) FUEL PUMP RELAY CONTROL CIRCUIT SHORTED TO GROUND
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
1.FUEL PUMP RELAY OPERATION
Ignition on, engine not running.
With the scan tool, read DTCs and record the related Freeze Frame data.
With the scan tool, actuate the Fuel Pump Relay.
Is the Fuel Pump Relay clicking?
Ye s>>
Refer to the INTERMITTENT CONDITIONSymptom (Diagnostic Procedure).
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.FUEL PUMP RELAY
Turn the ignition off.
Remove the Fuel Pump Relay.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the coil terminals of the Fuel Pump Relay.
Is the resistance between 50 and 90 ohms?
Ye s>>
Go To 3
No>>
Replace the Fuel Pump Relay.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.FUSED IGNITION SWITCH CIRCUIT OPEN
Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the Fused Ignition Switch Output circuit in the Fuel Pump
Relay connector.
Does the test light illuminate brightly?
Ye s>>
Go To 4
No>>
Repair the open or short to ground in the Fused Ignition Switch Output circuit. Inspect the related fuse
and repair as necessary.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
With ignition key on and battery voltage above 10.4 volts.
Set Condition:
An open or shorted condition is detected in the ASD Relay control circuit.
Possible Causes
GOOD TRIP EQUAL TO ZERO
ASD RELAY
(A14) FUSED B+ OUTPUT CIRCUITS
(K51) ASD RELAY CONTROL CIRCUIT OPEN
(K51) ASD RELAY CONTROL CIRCUIT SHORTED TO GROUND
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
1.GOOD TRIP EQUAL TO ZERO
Ignition on, engine not running.
With the scan tool, read DTCs and record the related Freeze Frame data.
Is the Good Trip Counter displayed and equal to zero?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITIONSymptom (Diagnostic Procedure).
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.ASD RELAY
Turn the ignition off.
Remove the ASD Relay from the PDC.
Measure the resistance between the coil terminals of the ASD Relay.
Is the resistance between 50 and 80 ohms?
Ye s>>
Go To 3
No>>
Replace the ASD Relay.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.(A14) FUSED B+ OUTPUT CIRCUIT
Using a 12-volt test light connected to ground, probe the (A14) Fused B+ Output circuits in the ASD Relay con-
nector.
Does the test light illuminate brightly?
Ye s>>
Go To 4
No>>
Repair the open or short to ground in the (A14) Fused B+ Output circuits. Inspect the related fuse and
repair as necessary.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
With the ignition key on and the engine speed greater than 0 RPM.
Set Condition:
When the PCM regulates the generator field and there are no detected field problems, but the voltage output
does not decrease.
Possible Causes
(K20) GENERATOR FIELD CONTROL CIRCUIT SHORTED TO GROUND
GENERATOR FIELD COIL SHORTED TO GROUND
BATTERY TEMPERATURE SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.CHARGING SYSTEM OPERATION
NOTE: Battery must be fully charged and be capable of passing a load test.
NOTE: Generator Belt tension and condition must be checked before continuing.
Ignition on, engine not running.
With the scan tool, read DTCs and the related Freeze Frame data then clear theDTCs.
With scan tool, actuate the Generator Field Driver.
With a 12-volt test light connected to ground, backprobe the (K20) Gen Field Control circuit in the back of Generator
Field harness connector.
Does the test light illuminate brightly and flash?
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.(K20) GEN FIELD CONTROL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C2 PCM harness connector.
Disconnect the Generator Field Harness connector.
Carefully inspect the related connectors for corrosion or spread termi-
nals before continuing.
Measure the resistance between ground and the (K20) Generator Field
Driver circuit at the Generator Field harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (K20) Generator Field
Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
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)
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)
6.(K125) GEN FIELD SOURCE CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the PCM harness connectors.
Disconnect the Generator Field harness connector.
Measure the resistance between ground and the (K125) Generator Field
Source circuit in the PCM harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (K125) Generator Field
Source circuit and replace the PCM.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 7
7.(K20) GEN FIELD CONTROL CIRCUIT OPEN
Measure the resistance of the (K20) Generator Field Driver circuit from
the Generator harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 8
No>>
Repair the open in the (K20) Generator Field Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
8.GENERATOR FIELD COIL HIGH RESISTANCE
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 9
Possible Causes
A/C SELECT CIRCUIT OPEN
A/C SELECT IN HVAC
PCM
A/C REQUEST CIRCUIT OPEN
REFRIGERATION SYSTEM NOT PROPERLY CHARGED
HIGH PRESS CUT-OFF SWITCH
LOW PRESSURE SWITCH
A/CCLUTCHCOIL
A/C COMPRESSOR CLUTCH GROUND CIRCUIT OPEN
(C3) A/C CLUTCH RELAY OUTPUT CIRCUIT OPEN
FUSED B+ CIRCUIT OPEN
A/CCLUTCHRELAY
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.DTC AND COMMUNICATION PRESENT
Ignition on, engine not running.
Verify that communication with the HVAC and PCM is available over the BUS.
With the scan tool, check for DTCs in the PCM and HVAC module.
Are any A/C DTC’s or communication failures present?
Ye s>>
Diagnose the related DTC(s) or BUS failure before continuing.
Perform BODY VERIFICATION TEST - VER 1.
No>>
Go To 2
2.A/C SELECT CIRCUIT OPEN
Engine running.
With the scan tool, read the A/C Select status in the PCM.
Turn the A/C Switch on and off a few times.
Does the A/C Select state change?
Ye s>>
Go To 3
No>>
Go To 12
3.A/C REQUEST CIRCUIT OPEN
Engine Running.
Turn the A/C system on and the fan on high.
With the scan tool in Inputs/Outputs, read the A/C request state.
Does the A/C request state change?
Ye s>>
Go To 4
No>>
Repair the open in the A/C Request circuit.
Perform BODY VERIFICATION TEST - VER 1.
4.REFRIGERATION SYSTEM NOT PROPERLY CHARGED
Turn the ignition off.
Verify that the Refrigerant System is properly charged per Service Procedure.
Is the Refrigerant System properly charged?
Ye s>>
Go To 5
No>>
Properly charge the Refrigerant System per Service Information.
Perform BODY VERIFICATION TEST - VER 1.
5.HIGH PRESSURE CUT-OFF SWITCH
Turn the ignition off.
Verify the High Pressure Cut-Off Switch operation per Service Information.
Is the High Pressure Cut-Off Switch OK?
Ye s>>
Go To 6
No>>
Replace the High Pressure Cut-Off Switch.
Perform BODY VERIFICATION TEST - VER 1.
6.LOW PRESSURE SWITCH
Turn the ignition off.
Verify the Low Pressure Switch operation per Service Information.
Is the Low Pressure Switch OK?
Ye s>>
Go To 7
No>>
Replace the Low Pressure Switch.
Perform BODY VERIFICATION TEST - VER 1.
7.A/C CLUTCH COIL
Ignition on, engine not running.
Disconnect the A/C Compressor Clutch harness connector.
Connect a test light between the ground circuit and the A/C Clutch Relay Output circuit.
With the scan tool, actuate the A/C Clutch Relay.
Does the test light illuminate brightly on and off with the relay actuation?
Ye s>>
Replace the A/C Clutch Coil.
Perform BODY VERIFICATION TEST - VER 1.
No>>
Go To 8
8.A/C COMPRESSOR CLUTCH GROUND CIRCUIT OPEN
Turn the ignition off.
Disconnect the A/C Clutch harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between ground and the A/C Compressor Clutch ground circuit in the A/C Clutch harness
connector.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 9
No>>
Repair the open in the A/C Compressor Clutch ground circuit.
Perform BODY VERIFICATION TEST - VER 1.