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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.
  1. Check the No. 43 (7.5 A) and the No. 10 (7.5 A) fuses in the under-dash fuse/relay box.
Are the fuses OK?
YES -
Go to Step 2 .
NO -
Replace the fuses, and recheck. If the fuses blow again, check for a short in the No. 43 (7.5 A) and No. 10 (7.5 A) fuses circuit.■
  1. Connect the HDS to the DLC.
  1. Start the engine.
  1. Turn on the A/C.
  1. Check the A/C switch in the PGM-FI Data List with the HDS.
Is the A/C switch on?
YES -
Go to Step 6 .
NO -
  1. Using the HDS, confirm the following values in the PGM-FI Data List at idle.
    TP sensor
    About 0.5 V
    RPM
    A/T
    740−840
    M/T
    700−800
    ECT SENSOR 2
    80−100 °C
    A/C SWITCH
    ON
    A/C CLUTCH
    ON
    A/C PRESSURE SENSOR
    196−3,138 kPa (2−32 kgf/cm 2 ) 28−455 psi
    A/C TEMPERATURE
    3.0 °C or more

Are all the values within specifications?
YES -
Go to Step 7 .
NO -
Troubleshoot the value that is not within the specifications.■
  1. Turn the ignition switch to LOCK (0).
Is the relay OK?
YES -
Go to Step 9 .
NO -
Replace the A/C compressor clutch relay .■
  1. Measure the voltage between the No. 1 terminal of the A/C compressor clutch relay 4P socket and body ground.
Is there battery voltage?
YES -
Go to Step 10 .
NO -
Repair open in the wire between the No. 43 (7.5 A) fuse in the under-dash fuse/relay box and the A/C compressor clutch relay.■

  1. Connect the No. 1 and No. 2 terminals of the A/C compressor clutch relay 4P socket with a jumper wire.
Does the A/C compressor clutch click?
YES -
Go to Step 11 .
NO -
Go to Step 21 .
  1. Disconnect the jumper wire.
  1. Turn the ignition switch to ON (II).

  1. Measure the voltage between the No. 4 terminal of the A/C compressor clutch relay 4P socket and body ground.
Is there battery voltage?
YES -
Go to Step 14 .
NO -
Repair open in the wire between the No. 10 (7.5 A) fuse in the under-dash fuse/relay box and the A/C compressor clutch relay.■
  1. Turn the ignition switch to LOCK (0).
  1. Reinstall the A/C compressor clutch relay.
  1. Make sure the A/C switch is OFF.
  1. Jump the SCS line with the HDS.
    NOTE: This step must be done to protect the engine control module (ECM)/powertrain control module (PCM) from damage.
  1. Disconnect ECM/PCM connector A (49P).

  1. Connect the ECM/PCM connector A (49P) No. 15 terminal to body ground with a jumper wire.
  1. 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 (49P). If the connections are good, substitute a known-good ECM/PCM, and recheck. If the symptom/indication goes away, replace the original ECM/PCM.
NO -
Repair open in the wire between the A/C compressor clutch relay and the ECM/PCM.■
  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 No. 2 terminal and the A/C compressor clutch 1P connector No. 1 terminal.
Is there continuity?
YES -
NO -
Repair open in the wire between the A/C compressor clutch relay and the A/C compressor clutch.■