Diagnostic Procedures
WARNING: This page is about a different car, the 2002 GMC Sonoma and 2002 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
- Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
- Install the scan tool. Start and idle the engine. Use a scan tool in order to monitor the CMP active counter. Does the scan tool indicate the CMP active counter is incrementing? If yes, go to next step. If no, go to step 4.
- Observe the Freeze Frame/Failure Records and data. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observe. See CONDITIONS FOR RUNNING DTC . Does the DTC reset? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
- Turn ignition off. Disconnect the CMP sensor connector. Turn ignition on, with engine off. With a test light connected to ground touch the 12-volt reference circuit. Does the test light illuminate? If yes, go to step 6. If no, go to next step.
- Turn ignition off. Disconnect the PCM connector C2. Test the 12-volt reference circuit of the CMP sensor for a short to ground, an open, or high resistance. Did you find and correct the condition? If yes, go to step 16. If no, go to step 12.
- Connect a test light to battery positive voltage. Touch the CMP sensor low reference circuit. Does the test light illuminate? If yes, go to step 8. If no, go to next step.
- Turn ignition off. Disconnect the PCM connector C2. Test the low reference circuit of the CMP sensor for an open. Did you find and correct the condition? If yes, go to step 16. If no, go to step 12.
- Start engine. Monitor the CAM signal active counter on the scan tool. Connect a 5-amp fused jumper wire to battery positive voltage and momentarily touch the signal circuit 5 times for a duration of 1 second each. Does the CAM signal change EACH time the signal circuit is touched? If yes, go to step 14. If no, go to next step.
- Did the fuse in the jumper wire open? If yes, go to step 11. If no, to next step.
- Test the signal circuit of the CMP sensor for a short to voltage or an open. Did you find and correct the condition? If yes, go to step 16. If no, go to step 12.
- Test the signal circuit of the CMP sensor for a short to ground. Did you find and correct the condition? If yes, go to step 16. If no, go to next step.
- Check for poor connections at PCM. Did you find and correct the condition? If yes, go to step 16. If no, go to next step.
- Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE under PROGRAMMING. After replacing PCM, go to step 16.
- Inspect for poor connections at the CMP sensor. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? If yes, go to step 16. If no, go to next step.
- Replace CMP sensor. After replacing sensor, go to next step.
- Use the scan tool in order to clear the DTCs. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If DTC 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.