- Perform the Battery Inspection/Test. See BATTERY TESTING & INSPECTION
in CHARGING SYSTEM article in ELECTRICAL. Does the battery pass the test? If so, go to next step.
- Install a scan tool. Turn ON the ignition, with the engine OFF. Does the scan tool power up? If so, go to next step. If not, go to SCAN TOOL DOES NOT POWER UP
in COMMUNICATION DEVICES article in ACCESSORIES & EQUIPMENT.
NOTE:
Lack of communication may be because of a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
- Turn ON the ignition, with the engine OFF. Attempt to communicate with the Powertrain Control Module (PCM). Does the scan tool communicate with the PCM on the class 2 serial data circuit? If so, go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE
in COMMUNICATION DEVICES article in ACCESSORIES & EQUIPMENT.
NOTE:
The symptom list in Symptoms will determine the correct diagnostic procedure to use.
- Select the DISPLAY DTCS FUNCTION for the PCM. Record all of the displayed DTCs, the DTC status, and the module which set the DTC. Does the scan tool display any DTCs? If so, go to next step. If not, go to SYMPTOMS - ENGINE ELECTRICAL under TROUBLE SHOOTING.
NOTE:
The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will collect all the available information before you perform tests.
- Does the scan tool display any DTCs which begin with a "U"? If so, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE
in COMMUNICATION DEVICES article in ACCESSORIES & EQUIPMENT. If not, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS .