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.
Press the engine start/stop button to select the OFF mode.

?2.
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.
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.
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. 23 (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 (A23) and the A/C compressor clutch relay, or other parts in the A/C systems.