Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, 2002 Chevrolet RV Cutaway, and 2002 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Remove any debris from the PCM connector surfaces before servicing the PCM. 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.

Inspect the HO2S signal circuit for being shorted to a PCM ground. The HO2S signal circuit shorted to a PCM ground sets a switching DTC.
A malfunction in the HO2S heater circuits will cause a DTC P1133 or P1153 to set. Check the HO2S heater circuits for intermittent opens or for loose connections. An oxygen supply inside the HO2S is necessary for proper operation.
This supply of oxygen is provided through the HO2S wires. Inspect all HO2S wires and connections for breaks or for contamination.
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 to help to determine how many miles have occurred since the DTC set. Use the Fail Counter and the Pass Counter in order to determine how many ignition cycles have occurred since 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.

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