Charging System No Code Test: Testing

NOTE: Verify that the battery is able to pass a load test before continuing.

Turn ignition on, engine not running. With the DRBIII(R), read the battery voltage and record the results. Measure battery voltage B+ to B- terminal and record the results. Compare the 2 voltage readings. Is the voltage difference less than one volt? If yes, go to next step. If no, go to Step 8 .
Ignition on, engine not running. Measure the voltage between the generator B+ terminal and the battery (+) post. Start the engine. Is the voltage above 0.4 volt? If yes, repair the B+ circuit for high resistance between the generator and battery. Perform POWERTRAIN VERIFICATION TEST VER-3 . If no, go to next step.
Ignition on, engine not running. Record all DTCs and freeze frame data, now erase codes. Carefully inspect all connectors for corrosion or spread terminals before continuing. With the DRBIII(R), actuate the generator field driver circuit. While back probing, measure the voltage of the generator field source (+) circuit at back of generator. Is the voltage above 10.0 volts? If yes, go to next step. If no, repair the generator field source (+) circuit for an open or short to ground. Perform POWERTRAIN VERIFICATION TEST VER-3 .

CAUTION: Ensure all wires are clear of moving parts.

Start the engine and warm to operating temperature. Measure the voltage between the generator case and battery (-) post. Is the voltage above 0.1 volt? If yes, repair generator ground for high resistance, generator case to battery (-) side. Perform POWERTRAIN VERIFICATION TEST VER-3 . If no, go to next step.
Turn the ignition off. Disconnect the generator field harness connector at back of the generator. Check connectors, clean and repair as necessary. Measure the resistance across the generator field terminals at the generator. Is the resistance above 15 ohms? If yes, replace or repair the generator as necessary. See GENERATOR under REMOVAL & INSTALLATION. Perform POWERTRAIN VERIFICATION TEST VER-3 . If no, go to next step.
Turn the ignition off. Disconnect the PCM harness connector. Check connectors, clean and repair as necessary. Measure the resistance of the generator field driver circuit between the PCM harness connector and the generator harness connector. Is the resistance below 5.0 volts? If yes, go to NEXT step. If no, repair the generator field driver circuit for an open. Perform POWERTRAIN VERIFICATION TEST VER-3 .
If there are no possible causes remaining, replace and program the PCM. See BODY CONTROL MODULES - LIBERTY under REMOVAL & INSTALLATION. Perform POWERTRAIN VERIFICATION TEST VER-3 .

NOTE: Battery condition must be verified prior to this test.

Turn the ignition off. Inspect the generator belt tension and condition. Is the generator belt OK? If yes, go to next step. If no, repair as necessary. Perform POWERTRAIN VERIFICATION TEST VER-3 .

NOTE: The test light should blink On and Off every 1.4 seconds.

Turn ignition on, engine not running. With the DRBIII(R), actuate the generator field. Using a 12-volt test light, back probe the generator field driver terminal at the back of the generator. While monitoring the 12-volt test light, wiggle the field terminals back to the PCM and ASD relay. Was there any interruption in the normal cycle of the test light? If yes, repair the wire or connector where the wiggling interrupted the voltage cycle. Perform POWERTRAIN VERIFICATION TEST VER-3 . If no, go to next step.
Start the engine. Turn on all accessories. Raise engine speed to 2000 RPM for 30 seconds then return to idle. With the DRBIII(R), read DTCs. Are there any "Charging System" Trouble Codes? If yes, refer to DIAGNOSTIC TROUBLE CODE IDENTIFICATION table under SELF-DIAGNOSTIC SYSTEM. Perform POWERTRAIN VERIFICATION TEST VER-3 . If no, test complete.