Inspection and Verification

INSPECTION AND VERIFICATION

WARNING:
- Batteries contain sulfuric acid and produce explosive gases. Work in a well-ventilated area. Do not allow the battery to come in contact with flames, sparks or burning substances. Avoid contact with skin, eyes or clothing. Shield eyes when working near the battery to protect against possible splashing of acid solution. In case of acid contact with skin or eyes, flush immediately with water for a minimum of 15 minutes, then get prompt medical attention. If acid is swallowed, call a physician immediately. Failure to follow these instructions may result in serious personal injury.
- Always lift a plastic-cased battery with a battery carrier or with hands on opposite corners. Excessive pressure on the battery end walls may cause acid to flow through the vent caps, resulting in personal injury and/or damage to the vehicle or battery.

CAUTION:
- Do not make jumper connections except as directed. Incorrect connections may damage the voltage regulator test terminals, fuses or fusible links.
- Do not allow any metal object to come in contact with the generator housing and internal diode cooling fins. A short circuit may result and burn out the diodes.

NOTE:
- While carrying out any pinpoint test, disregard any DTCs set while following a specific pinpoint test. After the completion of a test, be sure to clear all DTCs in the PCM.
- All voltage measurements are referenced to the negative (-) battery post unless otherwise specified.

1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical or electrical damage.

Visual Inspection Chart:

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. Verify the battery condition. Refer to Battery.
5. Check the operation of the charging system warning indicator at the instrument cluster (IC). Normal operation is as follows:
- With the key OFF, the charging system warning indicator should be off.
- With the key ON and the engine OFF, the charging system warning indicator should be on.
- With the engine running, the charging system warning indicator should be off.

6. Turn off the headlamps and the A/C system (if equipped). Turn the climate control blower to low/off. Check the battery voltage before and after starting the engine to determine if the battery voltage increases.

7. NOTE: Make sure to use the latest scan tool software release.

If the cause is not visually evident, connect the scan tool to the data link connector (DLC).

8. NOTE: The vehicle communication module (VCM) LED prove out confirms power and ground from the DLC are provided to the VCM.

If the scan tool does not communicate with the VCM:
- check the VCM connection to the vehicle.
- check the scan tool connection to the VCM.
- refer to Information Bus (Module Communications Network), No Power To The Scan Tool, to diagnose no communication with the scan tool.

9. If the scan tool does not communicate with the vehicle:
- verify the ignition key is in the ON position.
- verify the scan tool operation with a known good vehicle.
- refer to Information Bus (Module Communications Network) to diagnose no response from the PCM.

10. Carry out the network test.
- If the scan tool responds with no communication for one or more modules, refer to Information Bus (Module Communications Network).
- If the network test passes, retrieve and record continuous memory DTCs.

11. Clear the continuous DTCs and carry out the self-test diagnostics for the PCM and the IC.
12. If the DTCs retrieved are related to the concern, go to the DTC Chart. For all other DTCs, refer to Body Control Systems (Multifunction Electronic Control Module). Diagnostic Trouble Code Tests and Associated Procedures
13. If no DTCs related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures

NOTE: DTC P0622 can be set by the loss of the communication lines between the generator and the PCM. The charging system warning indicator then illuminates until the engine is operated at greater than 4,500 rpm (approximately wide open throttle [WOT]) for a minimum of 3 seconds. At this time, the generator self-excites. The charging system warning indicator remains illuminated, and the generator operates in a default mode (approximately 13.5 volts) until the engine is turned off.