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Home >> Chrysler >> 2002 >> Neon LE, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0320: No Crank Reference Signal At Pcm >> Testing

DTC P0320: No Crank Reference Signal At Pcm: Testing

  1. Turn the ignition on. With the DRBIII(R), read the CKP sensor state while cranking engine. Does the DRBIII(R) display Current CKP State Present while cranking the engine? If yes, go to next step. If no, go to step  6 .
    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 CKP sensor signal circuit in the PCM harness connector. Turn the ignition on (DO NOT start or crank the engine). Observe the lab scope screen. Look for any pulses generated by the CKP sensor. Did the CKP sensor generate any pulses? If no, go to next step. If yes, replace the CKP sensor.
    3. 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.
  3. Turn the ignition off. With the DRBIII(R) lab scope probe and the Miller Special Tool, backprobe the CMP sensor signal circuit in the PCM harness connector. Turn the ignition on (DO NOT start or crank the engine). Observe the lab scope screen. Look for any pulses generated by the CMP sensor. Did the CMP sensor generate any pulses? If yes, replace the CMP sensor. If no, go to next step.
    4. 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.
  4. Turn the ignition off. With the DRBIII(R) lab scope probe and the Miller Special Tool, backprobe the CKP sensor signal circuit in the PCM harness connector. Start the engine. Allow the engine to idle. Observe the lab scope screen while wiggling harness and connectors. Were there any irregularities in the lab scope pattern? If no, go to next step. If yes, check the harness connectors carefully. If okay, replace the CKP sensor.
    5. 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.
  5. Conditions that set DTC are not present at this time. The following list may help in identifying the intermittent condition:
    • With the engine running at normal operating temperature, monitor the DRBIII(R) parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set.
    • Review the DRBIII(R) Freeze Frame information to identify under what conditions the DTC set.
    • Refer to any Technical Service Bulletin (TSB) that may apply.
    • Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
    • Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.

      Were any of the above conditions present? If yes, repair as necessary. If no, test is complete.

  6. Turn the ignition off. Disconnect the CKP sensor harness connector. Turn the ignition on. Measure the voltage on the 8-volt supply circuit in the CKP sensor harness connector. Is the voltage 7.5-8.5 volts? If yes, go to next step. If no, go to step  15 .
  7. Measure the voltage on the CKP sensor signal circuit in the CKP sensor harness connector. Is the voltage 4.5-5.0 volts? If yes, go to next step. If no, go to step  10 .
  8. Turn the ignition off. Disconnect the PCM harness connectors. Measure the resistance of the sensor ground circuit between the CKP sensor harness connector and the PCM harness connector. Is the resistance less than 5.0 ohms? If yes, go to next step. If no repair the sensor ground circuit for an open.
  9. Inspect the slots on flywheel for damage. If a problem is found, repair as necessary. If there are no other possible causes remaining, replace the CKP sensor.
  10. Turn the ignition off. Disconnect the PCM harness connectors. Measure the resistance between ground and the CKP sensor signal circuit in the CKP sensor harness connector. Is the resistance less than 5.0 ohms? If yes, repair the CKP sensor signal circuit for a short to ground. If no, go to next step.
  11. Measure the resistance of the CKP sensor signal circuit between the CKP sensor harness connector and the PCM harness connector. Is the resistance less than 5.0 ohms? If yes, go to next step. If no, repair the CKP sensor signal circuit for an open.
  12. Turn the ignition off. Reconnect the PCM harness connectors. Turn the ignition on. Measure the voltage on the CKP sensor signal circuit in the CKP sensor harness connector. Is the voltage more than 5.0 volts? If yes, repair the CKP sensor signal circuit for a short to battery voltage. If no, go to next step.
  13. Turn the ignition off. Disconnect the PCM harness connectors. Measure the resistance between the CKP sensor signal circuit and the 8-volt supply circuit in the CKP sensor harness connector. Is the resistance less than 5.0 ohms? If yes, repair the CKP sensor signal circuit shorted to the 8-volt supply circuit. If no, go to next step.
  14. There are no possible causes remaining, replace PCM.
  15. Turn the ignition off. Disconnect the PCM harness connectors. Measure the resistance between ground and the 8-volt supply circuit in the CKP sensor harness connector. Is the resistance less than 100 ohms? If yes, repair the 8-volt supply circuit for a short to ground. If no, go to next step.
  16. Measure the resistance of the 8-volt supply circuit between the CKP sensor harness connector and the PCM harness connector. Is the resistance less than 5.0 ohms? If yes, go to next step. If no, repair the 8-volt supply circuit for an open.
  17. Turn the ignition off. Reconnect the PCM harness connectors. Turn the ignition on. Measure the voltage on the 8-volt supply circuit in the CKP sensor harness connector. Is the voltage more than 8.5 volts? If yes, repair the 8-volt supply circuit for a short to battery voltage. If no, go to next step.
  18. There are no possible causes remaining, replace PCM.
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