Diagnostic Aids

NOTE: Remove any debris from PCM connector surfaces before servicing PCM. Check PCM connector gaskets when diagnosing or replacing PCM. Ensure that gaskets are installed correctly to prevent water intrusion into PCM.

This diagnostic only runs once per ignition cycle. A malfunction in HO2S heater circuits causes a DTC to set. Check HO2S heater circuits for intermittent opens and for poor connections. The HO2S wires provide supply of oxygen. Check the HO2S wires and connections for breaks or for contamination.

Using the FREEZE FRAME/FAILURE RECORDS may help to locate an intermittent condition. If DTC cannot be duplicated, the information included in the FREEZE FRAME/FAILURE RECORDS can help determine how many miles since the DTC set. The fail and pass counter can also help determine how many ignition cycles the diagnostic reported a pass or a fail. In order to isolate when DTC failed, operate vehicle within the same FREEZE FRAME conditions. These conditions include, RPM, vehicle load and vehicle speed.