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 Initial Inspection and Diagnostic Overview, K20Z3 engine Initial Inspection and Diagnostic Overview.

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 fuse(s) blows again, check for a short in the No. 20 (7.5 A) fuse and the No. 36 (10 A) fuse circuits.�

2. Connect the HDS to the DLC.

3. Start the engine.

4. Turn on the A/C.

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 and 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 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, K20Z3 engine, and recheck. If the symptom/indication goes away, replace the original ECM/PCM; R18A1 engine , K20Z3 engine Service and Repair.�

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.�