A/C Signal Circuit Troubleshooting Idle Control System

Engine

A/C Signal Circuit Troubleshooting - Idle Control System


1. 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.






Do the current condition(s) match the threshold?
-YES- Go to step 2.
-NO- Do the A/C system test A/C System Test.

2. 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:

-1. Turn the ignition switch to LOCK (0).

-2. Turn the ignition switch to ON (II).

-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 A/C System Test.
-NO- Go to step 4.

4. Open wire check (A/C MG CLUTCH RLY CL- line):

-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.






-4. Turn the ignition switch to ON (II).

-5. Connect terminals A and B with a jumper wire.










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 PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, 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 Service and Repair.
-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 (A12) and the A/C compressor clutch relay, or other parts in the A/C systems.