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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 103 (Engine Controls Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0325: Knock Sensor Circuit (SOHC) >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. 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 - engine controls, go to next step.
    2. NOTE: If an engine knock can be heard, repair engine mechanical condition before proceeding with this test procedure.
  2. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate engine within code enable criteria or close to FREEZE FRAME/FAILURE RECORDS data that you observed. Does the scan tool indicate that this diagnostic failed this ignition? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  3. Disconnect KS harness. Set the Digital Multimeter (DMM) to the 400 k/ohm scale. Measure resistance of the KS using DMM connected to a good ground. Is resistance within 90-110 k/ohms? If yes, go to next step. If no, go to step  6.
    4. NOTE: DO NOT tap on plastic engine components.
  4. With DVOM still connected, set DVOM to measure AC frequency. Tap on engine block near appropriate KS while observing signal indicated on DVOM. Is any signal indicated on the DMM while tapping on the engine block near the KS? If yes, go to next step. If no, go to step  6.
  5. Disconnect 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 POWERTRAIN CONTROL MODULE in appropriate REMOVAL, OVERHAUL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE REPROGRAMMING  under PROGRAMMING. After replacing PCM, go to next step.
  9. Using scan tool, clear 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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