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.
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:
- 1. Check the A/C system - Refer to: A/C System InspectionA/C System Contamination Inspection .
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 vehicle to the OFF (LOCK) mode.
- 2. Turn the vehicle to the ON mode.
- 3. Activate the A/C CLUTCH in the INSPECTION MENU with the HDS.
A/C CLUTCH
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):
- 1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Jump the SCS line with the HDS, and wait more than 1 minute.
SCS Short
- 3. Disconnect the following connector.
PCM connector A (51P) - 4. Turn the vehicle to the ON mode.
- 5. Connect terminals A and B with a jumper wire.
Terminal A PCM connector A (51P) No. 13 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 an 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.