DTC P0622: Generator Field Not Switching Properly

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.

NOTE: Generator field switching is monitored when ignition is on and engine is running. DTC may be stored in Powertrain Control Module (PCM) when PCM tries to regulate the generator field with no results. Possible causes are: generator field driver circuit open or shorted, defective generator, defective PCM, defective Auto Shutdown (ASD) relay circuit, or defective connectors or wiring.

Turn ignition on with engine off. Using scan tool, actuate generator field driver. Using voltmeter, check voltage by backprobing terminal No. 1 (Dark Green/Orange wire) in round 2-wire connector at rear of the generator. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open on Dark Green/Orange wire between generator and ASD relay. ASD relay is located in power distribution center at driver's side front corner of engine compartment, near battery. Perform TEST VER-3A .
Ensure ignition is on with engine off. Using scan tool, actuate generator field driver. Using voltmeter, check voltage by backprobing terminal No. 2 (Dark Green wire) in round 2-wire connector at rear of the generator. If voltage cycles from low voltage to high voltage, go to next step. If voltage does not cycle from low voltage to high voltage, go to step 6 .
Ensure ignition is on with engine off. Using scan tool, clear DTCs from PCM. Using scan tool, actuate generator field driver. Wiggle wiring harness and connectors between generator and PCM with generator field driver actuated. PCM is located between driver's side front fender and power distribution center, near battery.
Using scan tool, check for DTCs. If DTC P0622: GENERATOR FIELD NOT SWITCHING PROPERLY does not exist, go to next step. If DTC P0622: GENERATOR FIELD NOT SWITCHING PROPERLY exists, repair wiring or connectors as necessary that caused DTC to return. Perform TEST VER-3A .
Turn ignition off. Inspect wiring harness and connectors between generator, PCM and ASD relay. ASD relay is located in power distribution center at driver's side front corner of engine compartment, near battery. If no problems exist, test is complete. If any problems exist, repair wiring or connectors as necessary. Perform TEST VER-3A .
Using scan tool, stop actuation of generator field driver. Turn ignition off. Disconnect PCM connectors. PCM is located between driver's side front fender and power distribution center, near battery.
Disconnect round 2-wire connector at rear of the generator. Using ohmmeter, check resistance between both generator field driver terminals inside the generator. These are the terminals that round 2-wire connector fits on at rear of the generator. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair or replace generator as necessary. Perform TEST VER-3A .
Ensure PCM connectors are still disconnected and round 2-wire connector is disconnected at rear of the generator. Using ohmmeter, check resistance between ground and terminal No. 2 (Dark Green wire) on round 2-wire connector for the generator. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Dark Green wire between generator and PCM. Perform TEST VER-3A .
Ensure PCM connectors are still disconnected and round 2-wire connector is disconnected at rear of the generator. Using ohmmeter, check resistance between terminal No. 2 (Dark Green wire) on round 2-wire connector for the generator and terminal No. 8 (Dark Green wire) on Black PCM connector C1. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-3A . If resistance is 5 ohms or more, repair open on Dark Green wire between PCM and generator. Perform TEST VER-3A .