DTC P0622: Generator Field Not Switching Properly: Testing
- Turn ignition on. Using scan tool, clear DTCs. Using scan tool, actuate generator field driver circuit. Using a voltmeter, backprobe between ground and terminal No. 1 (Dark Green/Orange wire) at generator harness connector. See Fig 1 or Fig 2 . If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair open in Dark Green/Orange wire between generator and Automatic Shutdown (ASD) relay. ASD relay is located in power distribution center. See Figure .
- Using scan tool, actuate generator field driver circuit. Using a voltmeter, backprobe between ground and terminal No. 2 (Dark Green wire) at generator harness connector. If voltage shifts from low to high, go to next step. If voltage does not shift from low to high, go to step 5 .
- Using scan tool, actuate generator field driver circuit. Wiggle wiring harness between generator and Powertrain Control Module (PCM). Stop driver circuit actuation. Using scan tool, retrieve DTCs. If DTC does not return, go to next step. If DTC returned, repair wiring harness as necessary where wiggling caused problem to appear.
- Turn ignition off. Inspect wiring and connectors for damage. If wiring and connectors are okay, test is complete. If wiring and connectors are not okay, repair or replace as necessary.
- Turn ignition off. Disconnect Powertrain Control Module (PCM) harness connectors. PCM is located to left of Power Distribution Center (PDC) in engine compartment, next to air cleaner. Disconnect generator harness connector. Inspect harness connectors and clean/repair as necessary. Measure resistance between terminal No. 1 and 2 at generator (component side). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair generator as necessary.
- Measure resistance in Dark Green wire between terminal No. 1 at generator harness connector and terminal No. 8 at PCM harness connector C1. See Figure , Fig 1 and Fig 2 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green wire between generator and PCM.
- Measure resistance between ground and terminal No. 8 (Dark Green wire) at PCM harness connector C1. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green wire between generator and PCM.
- If no other potential causes are remaining, replace PCM. After replacing PCM, PCM MUST be reprogrammed. See POWERTRAIN CONTROL MODULE under PROGRAMMING.