P0622

P0622-GENERATOR FIELD CONTROL CIRCUIT

Special Tools:










For a complete wiring diagram Refer to the Wiring Information.

- When Monitored:
With the ignition on. Engine running.

- Set Condition:
When the PCM tries to regulate the generator field with no result during monitoring. One Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC
1. 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.

2. Increase engine speed by pressing the accelerator pedal. Do not exceed 3500 rpm.
3. With the scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition Test

2. GENERATOR OPERATION




1. Ignition on, engine not running.

NOTE: The DTC needs to be cleared before actuating the Generator Field, if the DTC is not cleared, the Generator Field may not be allowed to actuate.

2. Using a 12-volt test light connected to ground, probe the (K20) Generator Field Control circuit in the Generator Field harness connector.
3. With a 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 accordingly during the actuation?

Yes

- Verify that there is good pin to terminal contact in the Generator and Powertrain Control Module connectors. Replace the Generator if no problems were found with the connectors.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 3

3. (K20) GEN FIELD CIRCUIT SHORTED VOLTAGE




1. Turn the ignition off.
2. Disconnect the C2 PCM harness connector.
3. Ignition on, engine not running.
4. Measure the voltage on the (K20) Gen Field Control circuit in the Generator Field harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the (K20) Gen Field Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 4

4. (K20) GEN FIELD CIRCUIT OPEN




1. 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 PCM Pinout Box (8815A) to perform diagnosis.

2. Measure the resistance of the (K20) Gen Field Control circuit from the Generator Field harness connector to appropriate terminal of the special tool #.

Is the resistance below 5.0 ohms?

Yes

- Go To 5

No

- Repair the open in the (K20) Gen Field Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. (K20) GEN FIELD CIRCUIT SHORTED TO GROUND




1. Measure the resistance between ground and the (K20) Gen Field Control circuit in the Generator Field harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the (K20) Gen Field Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Generator and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. 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.
4. Search for any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test