Diagnostic Aids

When diagnosing an intermittent problem, use scan tool to review malfunction history diagnostic information. This data can be used to duplicate a problem. If an injector, EST or EGR DTC is active and a misfire is active, diagnose those problems first. Use scan tool to monitor active misfire counts. Spraying water on wires will find bad wire(s). The scan tool active misfire counts should pick up an intermittent misfire problem. Watch scan tool misfire counter. When a specific cylinder misfires under certain load, conditions may be duplicated in the shop.

Use the IGNITION COMPONENT SPECIFICATION  Table to help in diagnosis.