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, hard acceleration or high/low pressure.
  • 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.
  1. Check the No. 7 (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 fuses and recheck. If fuses blow again, check for a short in the No. 7 (7.5 A) and No. 36 (10 A) fuse circuit.■
  1. Connect the HDS to the DLC.
  1. Start the engine.
  1. Turn on the A/C.
  1. Check the A/C CLUTCH in the PGM-FI Data List with the HDS.
Is the A/C CLUTCH on?
YES -
Go to Step 7 .
NO -
Go to Step 6 .
  1. Using the HDS, confirm the following values in the PGM-FI Date List at idle.
    TP SENSOR
    About 0.5 V
    RPM (min −1 )
    620±50−670±50
    ECT SENSOR 2
    176−212 °F (80−100 °C)
    A/C SWITCH
    ON
    A/C CLUTCH
    ON
    A/C PRESSURE SENSOR
    196−3,138 kPa (2−32 kgf/cm 3 ) [28−455 psi]

Are all the values within specifications?
YES -
Go to Step 7 .
NO -
Troubleshoot the value that is not within the specifications.■
Is the relay OK?
YES -
Go to Step 8 .
NO -
Replace the A/C compressor clutch relay .■
  1. 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 Step 9 .
NO -
  1. 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 .
  1. Disconnect the jumper wire.
  1. Turn the ignition switch ON (II).
  1. 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 Step 13 .
NO -
Repair 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.■
  1. Turn the ignition switch OFF.
  1. Reinstall the A/C compressor clutch relay.
  1. Jump the SCS line with the HDS.
    NOTE: This step must be done to protect the engine control module (ECM) from damage.
  1. Disconnect ECM connector A (44P).
  1. Connect the ECM connector A (44P) terminal No. 14 to body ground with a jumper wire.
  1. Turn the ignition switch ON (II).
Does the A/C compressor click?
YES -
Check for loose wires or poor connections at ECM connector A (44P). If the connections are good, check the ECM grounds. If the grounds are good, substitute a known-good ECM, and recheck. If the symptom/indication goes away, replace the original ECM. ■
NO -
Repair open in the wire between the A/C compressor clutch relay and the ECM.■
  1. Disconnect the jumper wire.
  1. Disconnect the A/C compressor clutch 1P connector.
  1. 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 -
NO -
Repair open in the wire between the A/C compressor clutch relay and the A/C compressor clutch.■