A/C Signal Circuit Troubleshooting
A/C Signal Circuit Troubleshooting
1.
A/C compressor clutch condition check:

A/C compressor clutch condition check
?1.
Start the engine, and let it idle.

?2.
Turn the blower switch on.

?3.
Turn the A/C switch on.

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

Do the current condition(s) match the threshold?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
2.
A/C system check:

A/C system check
?1.
Check the A/C system.

Does the A/C system operate?

     
YES
     
     
     
The A/C system circuit is OK.?
     
NO
     
     
     
Go to step 3.
3.
A/C compressor clutch circuit check:

A/C compressor clutch circuit check
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

?3.
Activate the A/C CLUTCH in the INSPECTION MENU with the HDS.

  

Is there a clicking noise from the A/C compressor clutch?

     
YES
     
     
     
The A/C compressor clutch circuit is OK. Do the A/C system test.
     
NO
     
     
     
Go to step 4.
4.
Open wire check (A/C MG CLUTCH RLY CL- line):

Open wire check (A/C MG CLUTCH RLY CL- line)
?1.
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

?2.
Jump the SCS line with the HDS.


?3.
Disconnect the following connector.

?4.
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

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


Is there a clicking noise from the A/C compressor clutch?

     
YES
     
     
     
The A/C MG CLUTCH RLY CL- wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM.?
     
NO
     
     
     
Check for poor connections or loose terminals at the A/C compressor clutch relay and the PCM. If the connections and terminals are OK, check the A/C compressor clutch relay. If needed, repair open in the A/C MG CLUTCH RLY CL- wire between the PCM (A13) and the A/C compressor clutch relay, or other parts in the A/C systems.