Test NTC-18: Checking Charging System

NOTE: For circuit identification, see WIRING DIAGRAMS article. If replacing Powertrain Control Module (PCM), PCM must be reprogrammed. See PROGRAMMING . After each repair procedure has been completed, reconnect all components. Perform TEST VER-3 to ensure system is functioning properly. Ensure no DTCs are present before performing this test. Ensure battery is in good condition and fully charged before proceeding with test procedure.

Inspect generator belt for damage and proper adjustment. If generator belt is in good condition and properly adjusted, go to next step. If generator belt is not in good condition or not properly adjusted, repair as necessary.
Start engine and let idle. Using scan tool, set engine speed to 2000 RPM for 30 seconds and then return engine to idle. Using scan tool, check for DTCs. If no DTCs exist for charging system, go to next step. If any DTCs for charging system exists, proceed to appropriate DTC test.
Turn ignition off. Turn ignition on. Using scan tool, actuate generator field driver. Using voltmeter, backprobe between ground and terminal No. 1 (Dark Green wire) at generator harness connector. Voltage should cycle from no voltage to battery voltage every 1.4 seconds. While monitoring voltage, wiggle wiring harness and connectors between generator and Powertrain Control Module (PCM), and between generator and Auto Shutdown (ASD) relay. PCM is located on left side of engine compartment, between Power Distribution Center (PDC) and Transmission Control Module (TCM). See Figure. If voltage changed, repair wiring harness as necessary where wiggling caused voltage to change. If voltage did not change, go to next step.
Using scan tool, check for DTCs. If no DTCs exist for charging system, go to next step. If any DTCs for charging system exists, proceed to appropriate DTC test.
Turn ignition off. Measure voltage between positive battery terminal and positive battery terminal on rear of generator. Start engine. If voltage is .4 volt or less, go to next step. If voltage is more than .4 volt, repair high resistance between positive battery terminal and positive battery terminal on rear of generator.
Turn ignition off. Measure voltage between case of generator and negative battery terminal. Start engine. If voltage is .1 volt or less, turn ignition off and go to next step. If voltage is more than .1 volt, repair generator for high resistance between generator case and negative battery terminal.
Turn ignition on. Using scan tool, read battery voltage. Record battery voltage displayed on scan tool. Measure voltage between positive and negative battery terminals. Compare voltage readings. If difference between voltage readings is one volt or more, go to next step. If difference between voltage readings is less than one volt, no problem is indicated at this time. Test is complete.
Turn ignition off. Disconnect Powertrain Control Module (PCM) connectors. PCM is located on left side of engine compartment, between Power Distribution Center (PDC) and Transmission Control Module (TCM). See Figure. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure voltage between ground and terminal No. 46 (Red/White wire) at PCM C2 harness connector. See Figure. If voltage is within one volt of voltage displayed on scan tool in previous step, go to next step. If voltage is not within one volt of voltage displayed on scan tool in previous step, repair open or high resistance in Red/White wire between PCM, fuse "N" (30-amp) and battery. Fuse "N" is located in PDC on left side of engine compartment.
At this time, PCM is assumed to be defective. Replace PCM.