P0622

P0622-GENERATOR FIELD NOT SWITCHING PROPERLY





For complete wiring diagrams refer to Diagrams/Electrical.


- When Monitored:

When the ignition is on.

- Set Condition:

The feedback signal does not match the commanded signal for the voltage regulator.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. GENERATOR

Turn the ignition off.

Disconnect the Generator field harness connector.

Check connectors - Clean/repair as necessary.

Measure the resistance between the generator field terminals.

Is the resistance between .5 and 15 Ohms?

Yes

- Go To 2

No

- Replace the Generator.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. (K20) GENERATOR FIELD DRIVER CIRCUIT OPEN





Disconnect the ECM harness connectors.

Check connectors - Clean/repair as necessary.

Measure the resistance of the (K20) Generator Field Driver circuit between the generator harness connector and the ECM harness connector.

Is the resistance less than 10 ohms.

Yes

- Go To 3

No

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

3. (K20) GENERATOR FIELD CIRCUIT SHORTED TO GROUND





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

Is the resistance less than 10 ohms.

No

- Repair the Generator field return shorted to Battery negative.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

Yes

- Go To 4

4. (K20) GENERATOR FIELD DRIVER CIRCUIT SHORTED TO VOLTAGE





Turn the ignition on.

Measure the voltage between the (K20) Generator Field Driver circuit in the generator harness connector and battery negative.

Is the voltage greater than 1 volt?

Yes

- Repair the (K20) Generator Field Driver circuit shorted to voltage.

No

- Go To 5

5. ECM

While monitoring with scan tool, connect a jumper wire between the driver circuit and the return circuit in the alternator connector.

Did the DTC return?

Yes

- Replace the ECM.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Repair complete.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test