Diagnostic Test
- ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
- Start the engine and allow it to reach operating temperature.WARNING:
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
- Increase engine speed by pressing the accelerator pedal. Do not exceed 3500 RPM.
- Using the scan tool, read the active DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
- Start the engine and allow it to reach operating temperature.
- GENERATOR OPERATION
- Turn the ignition off.
- Disconnect the Generator harness connector.
- Using a 12-Volt test light connected to ground, probe the (K20) Generator Field Control circuit in the Generator Field harness connector.
- Ignition on, engine not running.NOTE:
The DTC needs to be cleared before actuating the Solenoid, if the DTC is not cleared, the Solenoid may not be allowed to actuate.
- With the scan tool, actuate the Generator Field Driver.NOTE:
The test light should be illuminated and bright proportional to the maximum duty cycle allowed by the scan tool. For example, if the scan tool allows 100% actuation, the brightness should be as bright as a direct connection to the battery. If the scan tool allows a maximum 25% actuation, the brightness should be 25% as bright as a direct connection to the battery.
Does the test light illuminate brightly and flash on and off?
Yes
- Verify that there is good pin to terminal contact in the Generator and Powertrain Control Module connectors. If OK, replace the Generator. Refer to GENERATOR, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 3
- (K20) GEN FIELD CIRCUIT SHORTED TO VOLTAGE
- Turn the ignition off.
- Disconnect the PCM C2 harness connector.
- Ignition on, engine not running.
- Measure the voltage on the (K20) Gen Field Control circuit in the Generator Field harness connector.
Is there any voltage present?
Yes
- Repair the (K20) Gen Field Control circuit for a short to voltage.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 4
- CHECK THE (K20) GEN FIELD CIRCUIT FOR AN OPEN/HIGH RESISTANCE
- Turn the ignition off.CAUTION:
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.
- Connect the (special tool #10436, Adapter, GPEC Diagnostic).
- Measure the resistance of the (K20) Gen Field Control circuit between the Generator harness connector and the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 5
No
- Repair the (K20) Gen Field Control circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Turn the ignition off.
- CHECK THE (K20) GEN FIELD CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between ground and the (K20) Gen Field Control circuit in the Generator Field harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 6
No
- Repair the (K20) Gen Field Control circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance between ground and the (K20) Gen Field Control circuit in the Generator Field harness connector.
- POWERTRAIN CONTROL MODULE (PCM)
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Generator and the Powertrain Control Module (PCM).
- Look for any chafed, pierced, pinched or partially broken wires.
- Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Generator and Powertrain Control Module connectors.
- Perform any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Replace and program the Powertrain Control Module in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .