FixVault
Home › Chrysler › 2002 › PT Cruiser Base, Automatic › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0645: A/C Clutch Relay CKT › Testing

DTC P0645: A/C Clutch Relay CKT: Testing

  1. Turn the ignition on. With the DRBIII®, actuate the A/C Clutch Relay. Is the A/C Clutch Relay operating? If yes, go to next step. If no, go to step  5.
  2. With the DRBIII®, actuate the A/C Clutch Relay. Wiggle the wiring harness from the A/C Clutch Relay to the PCM while the relay is actuating. Did the A/C Clutch Relay stop when wiggling the wiring harness? If yes, repair as necessary. 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. With the engine running at normal operating temperature, monitor the DRBIII® 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® Freeze Frame information. If possible, try to duplicate the conditions under which the DTC was set. Refer to any Technical Service Bulletins (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.
  4. Turn the ignition off. Remove the A/C Clutch Relay from the PDC. Turn the ignition on. Measure the voltage on the Fused Ignition Switch Output circuit in the PDC. Is the voltage above 11.0 volts? If yes, go to next step. If no, repair the Fused Ignition Switch Output circuit. Check and replace any open fuses.
  5. Turn the ignition off. Measure the resistance of the A/C Clutch Relay between the Fused Ignition Switch Output terminal and the A/C Clutch Relay Control terminal. Is the resistance between 60 to 80 ohms? If yes, go to next step. If no, replace the A/C Clutch Relay.
  6. Turn the ignition off. Disconnect the PCM C2 harness connector. Measure the resistance of the A/C Clutch Relay Control circuit between the PDC and the PCM C2 harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the A/C Clutch Relay Control circuit for an open.
  7. Measure the resistance between ground and the A/C Clutch Control circuit in the PDC. Is the resistance below 5.0 ohms? If yes, repair the A/C Clutch Relay Control circuit for a short to ground. If no, go to next step.
  8. There are no possible causes remaining, replace the PCM. Program the new PCM. See PROGRAMMING .
About FixVault