- Powertrain/On-Board Diagnostic System Check

System Check:

DESCRIPTION
The 'Self-Diagnostic System Check' is an organized approach for identifying a problem caused by the on-board computer controlled electronics. Understanding this chart and using it correctly will reduce diagnosis time and prevent the unnecessary replacement of parts. If you have not reviewed the basic information on how to use the computer self-diagnostics, go to System Operation in this section.

NOTES ON TROUBLE TREES
1. If diagnostic system is not functional, a problem is present in the IPC or related wiring.

2. If trouble codes are present, they should be diagnosed in the order shown.

3. If no trouble codes are present then the chart will guide you to subsystem references for symptom diagnosis.

If no codes are set and no messages have been displayed, refer to the system performance check for the system exhibiting the condition.