Diagnostic Aids

WARNING: This page is about a different car, the 2002 GMC Sierra and 2002 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Before you service the PCM, remove any debris from the PCM connector surfaces. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.

Using the Freeze Frame/Failure Records may help to locate an intermittent condition. If you cannot duplicate the DTC, use the information in the Freeze Frame/Failure Records in order to determine how many miles have occurred since the DTC set. You can also use the Fail Counter and the Pass Counter in order to determine how many ignition cycles have occurred in which the diagnostic reported a pass or a fail. In order to isolate when the DTC failed, operate vehicle within the same Freeze Frame conditions that you observed. These conditions include:
1. The RPM.
2. The vehicle load.
3. The vehicle speed.
4. The temperature.
An oxygen supply inside the HO2S is necessary for proper operation. This oxygen supply is provided through the HO2S wires. Inspect all HO2S wires and connections for breaks or for contamination.

If an intermittent condition is suspected, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.