A/C Compressor Clutch Circuit Troubleshooting

• 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.
  

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-1)  More 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