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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.
  1. 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.
    NOTE: If an engine knock can be heard, repair engine mechanical condition before proceeding with this diagnostic.
  2. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate the engine within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observed. See CONDITIONS FOR RUNNING DTC . Does the scan tool indicate that this diagnostic failed this ignition? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  3. Disconnect the KS harness. Set the Digital Multimeter (DMM) to the 400K-ohm scale. Measure the resistance of the KS using the DMM connected to a good ground. Is the resistance of the KS within 90,000-110,000 ohms? If yes, go to next step. If no, go to step  6.
    NOTE: DO NOT tap on plastic engine parts.
  4. With DMM still connected, set DMM to 400 millivolts AC Hertz scale. Tap on engine block near KS while observing signal on DMM. If any signal is indicated while tapping on engine block? If yes, go to next step. If no, go to step  6.
  5. Disconnect the PCM connector. Test the KS signal circuit between the PCM and the KS connector for an open, short to voltage or short to ground. Did you find and correct the condition? If yes, go to step  9. If no, go to step  7.
  6. Replace KS. After replacing sensor, go to step  9.
  7. Inspect the KS signal circuit for a poor connection at the PCM or the KS harness connector. If you find a poor connection, repair the connector as necessary. Did you find and correct the condition? If yes, go to step  9. If no, go to next step.
  8. Replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  9. 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 no, go to step  2.
  10. 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.
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