intermittent codes

Diagnostic trouble codes displayed during the first pass of ECM diagnostic codes, and not the second pass, are considered intermittent. Intermittent diagnostic trouble codes are those that the ECM previously determined to be faulty but later tested good. If the diagnostic trouble code is intermittent, most charts will refer to a specific note. Do not bypass the charts when checking intermittent conditions. Failure to check an intermittent condition may result in replacement of good components.

Many intermittent problems are caused by poor electrical connections. Diagnosis should start with visual and physical inspection of connectors which are related with the diagnostic trouble code.