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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 379 (Engine Controls Self-Diagnostics - 3.4L) >> Diagnostic Tests >> DTC P0336: Crankshaft Position Sensor Performance >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. 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. Start the engine. Observe the 24 X parameter using a scan tool. Does 24 X RPM vary with engine speed up to approximately 1600 RPM? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position. Start the engine. Operate the vehicle within the Conditions For Running or as close to the Freeze Frame/Failure Records data observed. See CONDITIONS FOR RUNNING . Does the DTC fail this ignition? If yes, go to next step. If no, go to DIAGNOSTIC AIDS .
    4. WARNING: A short to ground on the cam or Crankshaft Position Sensor (CKP) 12-volt reference circuit can cause DTC 327 to set. Check this circuit for a short to ground before proceeding with this diagnostic table.
  4. Turn ignition switch to OFF position. Disconnect the CKP sensor "A" harness connector. Turn ignition switch to RUN position, engine OFF. Measure the voltage from the 12-volt reference circuit of the CKP sensor "A" to a good ground using the DMM. Does the voltage measure near battery voltage? If yes, go to step  6. If no, go to next step.
  5. Check the 12-volt reference circuit of the CKP sensor "A" for a short to ground or an open. Did you find and correct the condition? If yes, go to step  16. If no, go to step. If no, go to step  7.
  6. Connect a test light to battery voltage. Touch the CKP sensor "A" low reference circuit. Does test light illuminate? If yes, go to step  8. If no, go to next step.
  7. Check the low reference circuit of the CKP sensor "A" for an open or high resistance. Did you find and correct the condition? If yes, go to step  16. If no, go to step  12.
  8. Observe the 24X parameter on the scan tool. Connect a 5-amp fused jumper wire to battery positive voltage, momentarily touch the medium resolution engine speed signal circuit 5 times for a duration of one second each. Does 24 X RPM change each time the signal circuit is touched? If yes, go to step  13. If no, go to next step.
  9. Did the fuse in the jumper wire open? If yes, go to step  11. If no, go to next step.
  10. Check the medium resolution engine speed signal circuit of the CKP sensor A for the following conditions:
    • Any physical damage.
    • An open.
    • High resistance.

    Did you find and correct the condition? If yes, go to step  16. If no, go to step  12.

  11. Check the medium resolution engine speed signal circuit of the CKP sensor "A" for a short to ground. Did you find and correct the condition? If yes, go to step  16. If no, go to next step.
  12. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step  16. If no, go to step  15.
  13. Check for an intermittent and for a poor connection at the CKP sensor "A". Did you find and correct the condition? If yes, go to step  16. If no, go to step  15.
  14. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repair, go to step  16.
  15. Replace CKP sensor "A". After repair, go to next step.
  16. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions For Running. See CONDITIONS FOR RUNNING . Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  17. Using the scan tool, observe the stored information in 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 at this time.
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