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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Self-Diagnostics - 4.3L >> Diagnostic Tests >> DTC P0336: Crankshaft Position Sensor Circuit Performance >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
    2. NOTE: If DTC P0335 is also set, diagnose DTC P0335 before proceeding with this DTC. See DTC P0335: CRANKSHAFT POSITION SENSOR CIRCUIT .
  2. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. See CONDITIONS FOR RUNNING DTC . Did the DTC fail this ignition? If yes, go to next step. If no, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
  3. Inspect all of the CKP sensor circuits for wiring routed too closely to secondary ignition wires or components, wiring routed too closely to aftermarket add-on electrical equipment, or wiring routed to closely to solenoids, relays, and motors. Check for Electromagnetic Interference (EMI) in the CKP sensor circuits. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  4. Disconnect the CKP sensor connector. Measure the voltage from the 12-volt reference circuit of the CKP sensor with a DVOM. Is the voltage within battery voltage? If yes, go to next step. If no, go to step  13.
  5. Test the 12-volt reference circuit for an intermittent condition or shorted to other circuits. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  6. Test the low reference circuit for an intermittent condition. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  7. Test the CKP sensor signal circuit for an intermittent condition. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  8. Test for an intermittent and for a poor connection at the CKP sensor. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  9. Test for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  10. Remove the CKP sensor. Inspect CKP sensor for physical damage, improper installation, excessive play or looseness, excessive air gap between CKP sensor and reluctor wheel, foreign material passing between CKP sensor and reluctor wheel, or insufficient fuel. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  11. Inspect the reluctor wheel for physical damage, improper installation, or excessive end play or looseness. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  12. Replace CKP sensor. See appropriate REMOVAL & INSTALLATION article. After replacing sensor, go to next step.
  13. Replace PCM. See appropriate REMOVAL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  14. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  15. Observe the stored information, Capture Info with a scan tool. 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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