Intermittent Diagnostics

Intermittent diagnostics help find and isolate the cause of intermittent faults. Start with recreating a fault symptom and accumulating PCM data and comparing data to typical values. Analyze the results. Verify good engine and drivetrain mechanical conditions. Check any available Technical Service Bulletins (TSBs) and perform necessary repairs. Perform QUICK TEST  under SELF-DIAGNOSTIC SYSTEM and referenced DTC tests. If after diagnosis, symptom is still present, it is necessary to attempt to re-create the fault. Start with customer's information and description of symptom. If freeze frame data is available, it will be valuable in recreating conditions when fault occurred. See RE-CREATING FAULT CONDITIONS  table. Gather as much PCM PID data as possible. PID data should be gathered during different vehicle operating conditions as well as under conditions described by customer. Compare PCM PID data to known good data values. Examine PCM PID data for abnormal events or clearly incorrect values. Inspect signals for unexpected or abrupt changes. Cross check for agreement between related signals. See PIN VOLTAGE/PID VALUE CHARTS article.