DTC P0622: GENERATOR FIELD NOT SWITCHING PROPERLY

Monitor & Set Conditions

Generator field switching is monitored when ignition is on and when engine is running. DTC may be stored if Powertrain Control Module (PCM) tries to regulate generator field with no result during monitoring.

Possible Causes

• Intermittent Condition
• Generator Field Source (+) Circuit Open
• Generator Field Driver Circuit Short To Ground
• Generator Field Driver Circuit Open
• Generator Field Coil Open
• Generator Field Coil Shorted
• PCM

Testing

1. Turn ignition on with engine off. Using test light connected to ground, backprobe terminal No. 1 (Dark Green wire) on 2-wire connector at generator. Using scan tool, actuate generator field driver circuit. If test light blinks, go to next step. If test light does not blink, go to step 3 .

2. Turn ignition on with engine off. Using scan tool, read FREEZE FRAME data. Road test vehicle under conditions displayed in FREEZE FRAME data parameters. Using scan tool, actuate generator field driver circuit. Wiggle wiring harness between generator and PCM. PCM is located at passenger's side rear corner of engine compartment. Using scan tool, check for DTCs. If DTC P0622 resets, repair wiring and/or connection as necessary. If DTC P0622 does not reset, test is complete.

3. Using scan tool, check for DTCs. Record all DTCs and FREEZE FRAME data. Inspect PCM harness connectors and 2-wire connector at generator for corroded, damaged or pushed-out terminals. PCM is located at passenger's side rear corner of engine compartment. Using DVOM connected to ground, backprobe terminal No. 2 (Dark Blue wire) on 2-wire connector at generator. Using scan tool, actuate generator field driver circuit. If voltage is greater than 10 volts, go to next step. If voltage is 10 volts or less, repair open or high resistance in Dark Blue wire between generator and terminal No. 25 on PCM harness connector C3.

4. Turn ignition off. Disconnect PCM harness connectors. Disconnect generator connector. Using DVOM, measure resistance between ground and terminal No. 1 (Dark Green wire) on 2-wire connector at generator. If resistance is 100 ohms or greater, go to next step. If resistance is less than 100 ohms, repair short to ground in Dark Green wire between PCM and generator.

5. Measure resistance of Dark Green wire between terminal No. 1 on 2-wire connector at generator and terminal No. 10 on PCM harness connector C2. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open in Dark Green wire between PCM and generator.

6. Measure resistance between the 2 terminals on the generator. If resistance is .5-15.0 ohms, go to step 8 . If resistance is not .5-15.0 ohms, go to next step.

7. Repair or replace generator as necessary.

8. Replace and program PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.