Diagnostic Procedures
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
- Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM.
- Are any DTCs set other than DTC P0134 or DTC P0154? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
- With the engine at operating temperature, raise and hold the engine speed above 1200 RPM for 2 minutes. Observe the HO2S voltage display on the scan tool. Does the scan tool indicate HO2S voltage varying outside 400-500 mV? If yes, go to next step. If no, go to step 5.
- Review and record scan tool Failure Records data. Operate the vehicle within the Failure Records conditions. With the scan tool, observe the Specific DTC Information for this DTC until the test runs. Does the scan tool indicate this DTC passed? If yes, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
- Turn OFF the ignition. Disconnect the affected HO2S connector. Turn ON the ignition, with the engine OFF. Observe the HO2S voltage with a scan tool. Is the voltage above 1000 mV? If yes, go to step 8. If no, go to next step.
- Disconnect the affected HO2S harness connector. Turn ON the ignition, with the engine OFF. Jumper the HO2S high signal circuit and low signal circuit in the harness connector (PCM side). Observe the HO2S voltage display on the scan tool. Does the scan tool indicate an HO2S voltage below 75 mV? If yes, go to step 9. If no, go to next step.
- Turn OFF the ignition. Disconnect the PCM connector C1. Test for the following conditions:
- Open high signal circuit.
- Open low signal circuit.
- Poor terminal connections at the PCM.
If a condition is found, repair as necessary. Did you find and correct the condition? If yes, go to step 12. If no, go to step 11.
- Test the affected HO2S for a short to the HO2S bank 1 sensor 1 heater low control circuit. Did you find and correct the condition? If yes, go to step 12. If no, go to step 11.
- Inspect for poor terminal connections at the HO2S harness connector. If a condition is found, repair as necessary. Did you find and correct the condition? If yes, go to step 12. If no, go to next step.
- Replace the affected HO2S. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 12.
- Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE under PROGRAMMING. After repairs, go to next step.
- Use the scan tool in order to clear the DTCs. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step 2.
- With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.