Intermittent Diagnostic Techniques: Notes

Intermittent diagnostic techniques help find and isolate the root cause of intermittent faults associated with the electronic engine control (EEC) or the hybrid electric system. The information is organized to help find the fault and carry out the repair. The process of finding and isolating an intermittent fault starts with recreating a fault symptom, accumulating powertrain control module (PCM) data, and comparing that data to typical values, then analyzing the results. Refer to the scan tool users manual for the functions described below.

Before proceeding, be sure that:

• Customary mechanical system tests and inspections do not reveal a concern. (Remember, mechanical component conditions can make a PCM system react abnormally.)
• Technical Service Bulletins (TSBs) and On-line Automotive Service Information System (OASIS) messages, if applicable, are reviewed.
• Quick test and associated diagnostic sub-routines have been completed without finding a fault, and the symptom is still present.