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DTC P0320: No Crank Reference Signal At Pcm: Testing

  1. With the DRBIII®, read the Current CKP State while cranking the engine. Does the DRBIII® display Current CKP State Present while cranking the engine? If yes, go to next step. If no, go to step  4.
    2. NOTE: An intermittent failure with the Camshaft Position Sensor may cause DTC P0320 to set.
    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. Locate CMP Sensor. With the DRBIII® as a Dual Channel Lab Scope and the Miller Special Tool (6801), backprobe the CMP Sensor Signal circuit in the CMP Sensor connector and the PCM harness connector. Turn ignition on, engine not running. Wiggle the related wire harness and gently tap on the Camshaft Position Sensor. Observe the lab scope screen. Look for any pulses generated by the CMP Sensor. Now start the vehicle and wiggle the related wire harness. The Channel 1 and Channel 2 graphs should display the same readings on the DRBIII® screen. If they don't, you may have a bad connection or a wiring concern. Did the CMP Sensor generate any erratic pulses? If yes, replace the Camshaft Position Sensor. If no, go to next step.
    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. The conditions that set the DTC are not present at this time. The following may help in identifying the intermittent condition. Turn the ignition off. With the DRBIII® lab scope probe, in the dual channel function, and the Miller Special Tool (6801), backprobe the CKP Sensor Signal circuit in the PCM harness connector and the CKP Sensor harness connector. Wiggle the related wire harness and connections. Look for any pulses generated by the CKP while wiggling the harness and connectors. Start the engine. Observe the lab scope screen. Wiggle the related wire harness and connections. Look for any erratic pulses generated by the CKP Sensor. Did the CKP Sensor generate any irregular pulses in either of the above tests? If yes, check the wiring and connections that may cause the intermittent condition. If okay, replace the Crankshaft Position Sensor. If no, test is complete.
  4. Turn the ignition off. Disconnect the CKP Sensor harness connector. Turn ignition on, engine not running. Measure the voltage of the 5-Volt Supply circuit at the CKP Sensor harness connector. Is the voltage between 4.5 and 5.5 volts? If yes, go to next step. If no, go to step  13.
  5. Measure the voltage on the CKP Sensor Signal circuit at the CKP Sensor harness connector. Is the voltage between 4.5 and 5.0 volts? If yes, go to next step. If no, go to step  8.
  6. Turn the ignition off. Measure the resistance of the Sensor Ground circuit from the CKP Sensor harness connector to the PCM harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the Sensor Ground circuit for an open.
    7. NOTE: Inspect the slots on the flywheel for damage. If a problem is found, repair as necessary.
  7. There are no possible causes remaining, replace the Crankshaft Position Sensor.
  8. Turn the ignition off. Ensure the CKP Sensor is disconnected. Measure the resistance between ground and the CKP Sensor Signal circuit at the CKP Sensor harness connector. Is the resistance below 100 ohms? If yes, repair the CKP Sensor Signal circuit for a short to ground. If no, go to next step.
  9. Ensure the ignition is off. Disconnect the PCM harness connectors. Measure the resistance of the CKP Sensor Signal circuit from the CKP Sensor harness connector to the PCM harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the CKP Sensor Signal circuit for an open.
  10. Ensure the ignition is off. Reconnect PCM connectors. Turn ignition on, engine not running. Measure the voltage of the CKP Sensor Signal circuit at the CKP Sensor harness connector. Is the voltage above 5.0 volts? If yes, repair the CKP Sensor Signal circuit for a short to battery voltage. If no, go to next step.
  11. Turn the ignition off. Ensure the CKP Sensor is disconnected. Disconnect the PCM harness connectors. Measure the resistance between the CKP Sensor Signal circuit and the 5-Volt Supply circuit at the CKP Sensor harness connector. Is the resistance below 5.0 ohms? If yes, repair the CKP Sensor Signal circuit shorted to the 5-Volt Supply circuit. If no, go to next step.
  12. There are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .
  13. Turn the ignition off. Disconnect the PCM harness connectors. Ensure the CKP Sensor is disconnected. Measure the resistance between ground and the 5-Volt Supply circuit at the CKP Sensor harness connector. Is the resistance below 100 ohms? If yes, repair the 5-Volt Supply circuit for a short to ground. If no, go to next step.
  14. Measure the resistance of the 5-Volt Supply circuit from the CKP Sensor harness connector to the PCM harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the 5-Volt Supply circuit for an open.
  15. Turn the ignition off. Reconnect PCM connectors. Turn ignition on, engine not running. Measure the voltage of the 5-Volt Supply circuit at the CKP Sensor harness connector. Is the voltage above 5.3 volts? If yes, repair the 5-Volt Supply circuit for a short to battery voltage. If no, go to next step.
  16. There are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .
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