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Home >> Dodge and Ram >> 2003 >> Durango Base, 5.9 Z, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Engine Controls - Self-Diagnostics - 3.9L & 5.9L) >> Diagnostic Tests >> DTC P1391: Intermittent Loss Of CMP Or CKP >> Testing

DTC P1391: Intermittent Loss Of CMP Or CKP: Testing

WARNING: This page is about a different car, the 2003 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: When the engine is operating, DO NOT stand in a direct line with the fan. DO NOT put your hands near the pulleys, belts or fan. DO NOT wear loose clothing.
  1. Turn ignition on, with engine off. With the DRBIII(R) scan tool, read the DTCs and record the related freeze frame data. Start the engine and run until operating temperature is reached (closed Loop). It may be necessary to test drive the vehicle. Does the DTC reset? If yes, go to next step. If no, see INTERMITTENT CONDITION  under SELF-DIAGNOSTIC SYSTEM.
    2. WARNING: When the engine is operating, DO NOT stand in a direct line with the fan. DO NOT put your hands near the pulleys, belts or fan. DO NOT wear loose clothing.
  2. Turn the ignition off. With the DRBIII(R) lab scope probe and the Miller Special Tool (6801), backprobe the (K44) CMP sensor signal circuit in the CMP harness connector. Start the engine. Observe the lab scope screen. Are there any irregular or missing signals? If yes, go to next step. If no, go to step  6 .
  3. Turn the ignition off. Visually inspect the related wire harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals. Ensure the CKP sensor and the CMP sensor are properly installed and the mounting bolt(s) are tight. Refer to any Technical Service Bulletin (TSB) that may apply. Were any of the above conditions present? If yes, repair as necessary. If no, go to next step.
  4. Remove the CMP sensor. Inspect the tone wheel/pulse ring for damage, foreign material, or excessive movement. Were any problems found? If yes, repair or replace as necessary. If no, go to next step.
  5. There are no possible causes remaining, replace CMP sensor.
    6. WARNING: When the engine is operating, DO NOT stand in a direct line with the fan. DO NOT put your hands near the pulleys, belts or fan. DO NOT wear loose clothing.
  6. Turn the ignition off. With the DRBIII(R) scan tool as a dual channel lab scope and the Miller Special Tool (6801), backprobe the (K44) CMP signal circuit in the CMP harness connector and the PCM harness connector. Start the engine. Observe the lab scope screen. Wiggle the related wire harness and gently tap on the CMP sensor. Look for any differences between the Channel 1 and Channel 2 patterns generated by the CMP sensor. Does the DRBIII(R) scan tool screen display any missing or irregular patterns? If yes, replace the CMP sensor or repair the wiring/connection concern. If no, go to next step.
    7. WARNING: When the engine is operating, DO NOT stand in a direct line with the fan. DO NOT put your hands near the pulleys, belts or fan. DO NOT wear loose clothing.
  7. Turn the ignition off. With the DRBIII(R) lab scope probe and the Miller Special Tool (6801), backprobe the (K24) CKP signal circuit in the CKP harness connector. Start the engine. Observe the lab scope screen. Are there any irregular or missing signals? If yes, go to next step. If no, go to step  11 .
  8. Turn the ignition off. Visually inspect the related wire harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals. Ensure the CKP sensor and the CMP sensor are properly installed and the mounting bolt(s) are tight. Refer to any Technical Service Bulletin (TSB) that may apply. Were any of the above conditions present? If yes, repair as necessary. If no, go to next step.
  9. Remove the CKP sensor. Inspect the tone wheel/flex plate slots for damage, foreign material, or excessive movement. Were any problems found? If yes, repair or replace as necessary. If no, go to next step.
  10. There are no possible causes remaining, replace CKP sensor.
    11. WARNING: When the engine is operating, DO NOT stand in a direct line with the fan. DO NOT put your hands near the pulleys, belts or fan. DO NOT wear loose clothing.
  11. Conditions that set DTC are not present at this time. The following list may help in identifying the intermittent condition:
    • Turn the ignition off. With the DRBIII(R) scan tool as a dual channel lab scope and the Miller Special Tool (6801), backprobe the (K24) CKP sensor signal circuit in the PCM harness connector and CKP harness connector. Both of the graphs should be the same.
    • Start the engine. Monitor the DRBIII(R) lab scope screen. Both patterns should be the same.
    • Wiggle the related wire harness and gently tap on the CKP sensor. Look for any differences between Channel I and Channel 2 patterns generated by the CKP sensor.

    Were any erratic or missing signals noticed? If yes, replace the CKP sensor. If no, test is complete.

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