LEMON Manuals: Even more car manuals for everyone
Home >> Chrysler >> 2002 >> PT Cruiser Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0646: A/C Clutch Relay Control Circuit Low >> Testing

DTC P0646: A/C Clutch Relay Control Circuit Low: 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  3.
    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. 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.
  3. Turn the ignition off. Disconnect the A/C Clutch harness connector. Using a 12-volt test light connect to B+, probe the Ground circuit in the A/C Clutch harness connector. Does the test light illuminate brightly? If yes, go to next step. If no, repair the Ground circuit for an open.
  4. With the DRBIII®, actuate the A/C Clutch Relay. Measure the voltage of the A/C Clutch Relay Output circuit in the A/C Clutch harness connector. Is the voltage above 11.0 volts? If yes, replace the A/C Clutch. If no, go to next step.
  5. Turn the ignition off. Remove the A/C Clutch Relay from the PDC. Using a 12-volt test light connected to ground, probe the Fused B+ circuit in the PDC. Does the test light illuminate brightly? If yes, go to next step. If no, repair the Fused B+ circuit for a short to ground or open. Inspect fuses and replace as necessary.
  6. Measure the resistance of the A/C Clutch Output circuit from the PDC to the A/C Clutch harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the open in the A/C Clutch Relay output circuit.
  7. Measure the resistance between ground and the A/C Clutch Relay Control Circuit at the A/C Clutch harness connector. Is the resistance below 100 ohms? If yes, repair the A/C Clutch Relay Output circuit for a short to ground. If no, go to next step.
  8. Turn the ignition on. Using a 12-volt test light connected to ground, probe the Fused Ignition Switch circuit in the PDC. Does the test light illuminate brightly? If yes, go to next step. If no, repair the Fused Ignition circuit for an open or short to ground.
  9. 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.
  10. Ensure the ignition is 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.
  11. Measure the resistance between ground and A/C Clutch Relay Control circuit at the PDC. Is the resistance below 100 ohms? If yes, repair the A/C Clutch Relay Control circuit for a short to ground. If no, go to next step.
  12. There are no possible causes remaining, replace the PCM. Program the new PCM. See PROGRAMMING .
scientia non olet · About LEMON Manuals