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 index.
  • Before doing any symptom troubleshooting, check for powertrain DTCs, except K20Z2 engine, K20Z2 engine.

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 2.


NO - Replace the fuses and recheck.n


2.Connect the HDS to the DLC.

3.Start the engine.

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

5.Check the A/C CLUTCH in the PGM-FI Data List with the HDS.

Is the A/C CLUTCH on?


YES - Go to 7.


NO - Go to 6.


6.Check the engine coolant temperature and idle speed (use the HDS PGM-FI data list if possible).

ECT Sensor 2 80-100 °C (176-212 °F) 
TP sensor About 0.5 V at idle 
RPM (min-1More than 670 

Are the coolant temperature and idle speed OK?


YES - Go to 7.


NO - Troubleshoot and repair the cause of the high engine coolant temperature, or low idle.n

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

Is the relay OK?


YES - Go to 8.


NO - Replace the  A/C compressor clutch relay.n


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

 

Is there battery voltage?


YES - Go to 9.


NO - Replace the under-hood fuse/relay box.n

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 10.


NO - Go to 18.


10.Disconnect the jumper wire.

11.Turn the ignition switch ON (II).

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

 

Is there battery voltage?


YES - Go to 13.


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

13.Turn the ignition switch OFF.

14.Reinstall the A/C compressor clutch relay.

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

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

 

17.Turn the ignition switch ON (II).

Does the A/C compressor click?


YES - Check for loose wires or poor connections at ECM/PCM connector A (44P). If the connections are good, check the ECM/PCM grounds. If the grounds are good, substitute a known-good ECM/PCM, and recheck. If the symptom/indication goes away, replace the original ECM/PCM, then do the ECM/PCM idle learn procedure, except K20Z2 engine, K20Z2 engine.n


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

18.Disconnect the jumper wire.

19.Disconnect the A/C compressor clutch 1P connector.

20.Check for continuity between the A/C compressor clutch relay 4P socket terminal No. 2 and the A/C compressor clutch 1P connector terminal No. 1.

 

Is there continuity?


YES - Check the A/C compressor clutch clearance, and the compressor clutch field coil. Repair as needed.n


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