Intermittent Diagnostic Techniques: Notes

Intermittent diagnostic techniques help find and isolate the root cause of intermittent concerns associated with the powertrain control module (PCM). The material is organized to help find the concern and carry out the repair. There are examples that illustrate the diagnostic techniques. The process of finding and isolating an intermittent starts with recreating a concern symptom, accumulating PCM data, comparing that data to typical values, and analyzing the results.

Before proceeding, make sure that:

• Customary mechanical system tests and inspections do not reveal a problem. (Remember, mechanical component problems can make a PCM system react abnormally.)
• Review the Technical Service Bulletins (TSBs) and OASIS messages, if available.
• The Quick Test and associated pinpoint diagnoses have been completed without finding a concern, and the symptom is still occurring.