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 index.
Before doing symptom troubleshooting, check for PGM-FI DTCs.
1.
HVAC control system check:

HVAC control system check
?1.
Connect the HDS to the DLC.

?2.
Start the engine.

?3.
Set the A/C button and the blower control dial to ON.

?4.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
A/C SWITCH
ON
      
A/C CLUTCH
ON
      

Do the current condition(s) match the threshold?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
A/C SWITCH is OFF, go to the A/C signal circuit troubleshooting.?
     
NO
     
     
     
A/C SWITCH is ON and A/C CLUTCH is OFF, update the PCM if it does not have the latest software, or substitute a known-good PCM, and recheck.?
2.
Fuse check:

Fuse check
?1.
Check the following fuse.
Fuse
No. A27 (7.5 A)
Location
Under-hood fuse/relay box

Is the fuse OK?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
Replace the fuse, and recheck. If the fuse blows again, repair a short in the No. A27 (7.5 A) fuse circuit.?
3.
A/C compressor clutch relay check:

A/C compressor clutch relay check
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Remove the A/C compressor clutch relay from the under-hood fuse/relay box, and test it.

Is the relay OK?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Replace the A/C compressor clutch relay.?
4.
Open wire check (+B MG CLUTCH line):

Open wire check (+B MG CLUTCH line)
?1.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
A/C compressor clutch relay: disconnected
Test point 1
A/C compressor clutch relay 4P socket No. 1
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The +B MG CLUTCH wire is OK. Go to step 5.
     
NO
     
     
     
Repair an open in the wire between the No. A27 (7.5 A) fuse in the under-hood fuse/relay box and the A/C compressor clutch relay.?
5.
Determine possible failure area (A/C compressor clutch relay switch side circuit, A/C compressor clutch relay coil side circuit):

Determine possible failure area (A/C compressor clutch relay switch side circuit, A/C compressor clutch relay coil side circuit)
?1.
Connect terminals A and B with a jumper wire.
Terminal A
A/C compressor clutch relay 4P socket No. 1
Terminal B
A/C compressor clutch relay 4P socket No. 2


Does the A/C compressor clutch click?

     
YES
     
     
     
Go to step 6.
     
NO
     
     
     
Go to step 8.
6.
Open wire check (IG2 A/C line):

Open wire check (IG2 A/C line)
?1.
Disconnect the jumper wire.

?2.
Turn the vehicle to the ON mode.

?3.
Measure the voltage between test points 1 and 2.
Test condition
Vehicle ON mode
A/C compressor clutch relay: disconnected
Test point 1
A/C compressor clutch relay 4P socket No. 7
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The IG2 A/C wire is OK. Go to step 7.
     
NO
     
     
     
Repair an open in the wire between the No. B22 (7.5 A) fuse in the under-dash fuse/relay box and the A/C compressor clutch relay in under-hood fuse/relay box.?
7.
Open wire check (A/C MG CLUTCH RLY CL- line):

Open wire check (A/C MG CLUTCH RLY CL- line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Reinstall the A/C compressor clutch relay.

?3.
Jump the SCS line with the HDS, and wait more than 1 minute.

NOTE: This step must be done to protect the PCM from damage.

?4.
Disconnect the following connector.
PCM connector A (51P)

?5.
Connect terminals A and B with a jumper wire.
Terminal A
PCM connector A (51P) terminal No. 13
Terminal B
Body ground

?6.
Turn the vehicle to the ON mode.

Does the A/C compressor clutch click?

     
YES
     
     
     
Update the PCM if it does not have the latest software, or substitute a known-good PCM, and recheck.?
     
NO
     
     
     
Repair an open in the wire between the A/C compressor clutch relay and the PCM.?
8.
Open wire check (A/C MG CLUTCH line):

Open wire check (A/C MG CLUTCH line)
?1.
Disconnect the jumper wire.

?2.
Disconnect the following connector.
A/C compressor clutch 3P connector

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
A/C compressor clutch relay: disconnected
A/C compressor clutch 3P connector: disconnected
Test point 1
A/C compressor clutch relay 4P socket No. 2
Test point 2
A/C compressor clutch 3P connector No. 1


Is there continuity?

     
YES
     
     
     
     
NO
     
     
     
Repair an open in the wire between the A/C compressor clutch relay and the A/C compressor clutch.?