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Home >> Buick >> 2003 >> Century Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 3.1L Engine >> Diagnostic Tests >> DTC P0341: CMP Sensor Circuit Performance >> Diagnostic Procedure

Diagnostic Procedure

  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 CMP sensor signal present parameter using a scan tool. Does the scan tool indicate the CMP sensor signal is present? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions For Running Test. See CONDITIONS FOR RUNNING TEST . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC reset? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  4. Turn ignition switch to OFF position. Remove the power steering pump. Disconnect the CMP sensor harness connector. Turn ignition switch to RUN position, engine OFF. Probe the 12-volt reference circuit of the CMP sensor harness connector using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  8.
  5. Turn ignition switch to OFF position. Jumper the CMP circuits from the CMP sensor to the CMP sensor harness connector. Turn ignition switch to RUN position, engine OFF. Measure the Voltage Drop from the low reference circuit of the CMP sensor to a good ground using a DMM. Is the voltage more than 0.2 volt? If yes, go to step  9. If no, go to next step.
  6. Remove the jumpers from the CMP circuits. Start the engine. Observe the CMP sensor signal on the scan tool. Momentarily and repeatedly probe the signal circuit of the CMP sensor using a test light connected to battery voltage. Does the CMP sensor signal change when the test light contacts the signal circuit? If yes, go to step  12. If no, go to next step.
  7. Turn ignition switch to RUN position, engine OFF. Probe the signal circuit of the CMP sensor harness connector using a test light connected to a good ground. Does the test light illuminate? If yes, go to step  11. If no, go to step  10.
  8. Test the CMP 12-volt reference circuit between the CMP sensor and the PCM for an open or for high resistance. Did you find and correct the condition? If yes, go to step  18. If no, go to step  13.
  9. Test the CMP Low reference circuit between the CMP sensor and the PCM for an open or high resistance. Did you find and correct the condition? If yes, go to step  18. If no, go to step  13.
    10. NOTE: Disconnecting the PCM may remove the short from the circuit.
  10. Test the CMP signal circuit between the CMP sensor and the PCM for a open or for a short to ground. Did you find and correct the condition? If yes, go to step  18. If no, go to step  13.
    11. NOTE: Disconnecting the PCM may remove the short from the circuit.
  11. Test the CMP signal circuit between the CMP sensor and the PCM for a short to voltage. Did you find and correct the condition? If yes, go to step  18. If no, go to step  13.
  12. Test for an intermittent and for poor connections at the CMP harness connector. Did you find and correct the condition? If yes, go to step  18. If no, go to step  14.
  13. Test for an intermittent and for poor connections at the PCM harness connector. Did you find and correct the condition? If yes, go to step  18. If no, go to step  17.
  14. Remove the CMP sensor. Visually inspect the CMP sensor for physical damage and for loose or improper installation. Did you find and correct the condition? If yes, go to step  18. If no, go to next step.
  15. Visually inspect the CMP sensor reluctor wheel for damage. If the CMP reluctor wheel is damaged, diagnose mechanical problem. Go to appropriate article in ENGINES. Did you find and correct the condition? If yes, go to step  18. If no, go to next step.
  16. Replace CMP sensor. After repair, go to step  18.
  17. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  18. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions For Running Test. See CONDITIONS FOR RUNNING TEST . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  19. 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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