A/C Compressor Clutch Circuit Troubleshooting

A/C Compressor Clutch Circuit Troubleshooting

NOTE:

- It is normal for the A/C compressor to turn off under certain conditions, such as low idle, high engine coolant temperature, or hard acceleration.

- Do not use this troubleshooting procedure if the fans are also inoperative with the A/C on. Refer to the symptom troubleshooting.

- Before doing any symptom troubleshooting, check for powertrain DTCs; R18A1 engine, Reading and Clearing Diagnostic Trouble Codes K20Z3 engine. Reading and Clearing Diagnostic Trouble Codes

1. Check the No. 20 (7.5 A) fuse in the under-hood fuse/relay box, and the No. 36 (10 A) fuse in the under-dash fuse/relay box.

Are the fuses OK?
YES - Go to step 2.

NO - Replace the fuse(s), and recheck. If the fuses blow again, check for a short in the No. 20 (7.5 A) and No. 36 (10 A) fuses circuit.


2. Connect the HDS to the DLC.

3. Start the engine.

4. Turn on the A/C on the HVAC control unit.

5. Using the HDS, confirm the following values in the PGM-FI Data List at idle.





Are all the values within specifications?
YES - Go to step 6.

NO - Troubleshoot the value that is not within the specifications.


6. Turn the ignition switch to LOCK (0).

7. Remove the A/C compressor clutch relay from the under-hood fuse/relay box, and test it. Testing and Inspection

Is the relay OK?
YES - Go to step 8.

NO - Replace the A/C compressor clutch relay.


8. Measure the voltage between A/C compressor clutch relay 4P socket terminal No. 1 and body ground.

Is there battery voltage?
YES - Go to step 9.

NO - Replace the under-hood fuse/relay box. Under-Hood Fuse/Relay Box Removal/Installation






9. Connect the A/C compressor clutch relay 4P socket terminals No. 1 and No. 2 with a jumper wire.

Does the A/C compressor clutch click?
YES - Go to step 10.

NO - Go to step 19.






10. Disconnect the jumper wire.

11. Turn the ignition switch to ON (II).

12. Measure the voltage between A/C compressor clutch relay 4P socket terminal No. 3 and body ground.

Is there battery voltage?
YES - Go to step 13.

NO - Repair an open in the wire between the No. 36 (10 A) fuse in the under-dash fuse/relay box and the A/C compressor clutch relay.






13. Turn the ignition switch to LOCK (0).

14. Reinstall the A/C compressor clutch relay.

15. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the engine control module/powertrain control module (ECM/PCM) from damage.

16. Disconnect ECM/PCM connector A (44P).

17. Connect ECM/PCM connector A (44P) terminal No. 14 to body ground with a jumper wire.

18. Turn the ignition switch to ON (II).

Does the A/C compressor click?
YES - Check for loose wires or poor connections at ECM/PCM connector A (44P) terminal No. 14. If the connections are good, check the ECM/PCM grounds. If the grounds are good, substitute a known-good ECM/PCM; R18A1 engine, Reading and Clearing Diagnostic Trouble Codes K20Z3 engine, Reading and Clearing Diagnostic Trouble Codes and recheck. If the symptom/indication goes away, replace the original ECM/PCM.

NO - Repair an open in the wire between the A/C compressor clutch relay and the ECM/PCM.






19. Disconnect the jumper wire.

20. Disconnect the A/C compressor clutch 3P connector.

21. Check for continuity between A/C compressor clutch relay 4P socket terminal No. 2 and A/C compressor clutch 3P connector terminal No. 2.

Is there continuity?
YES - Check the A/C compressor clutch clearance, and the A/C compressor clutch field coil. Testing and Inspection Repair as needed.

NO - Repair an open in the wire between the A/C compressor clutch relay and the A/C compressor clutch.