A/C Signal Circuit Troubleshooting

A/C Signal Circuit Troubleshooting

1. Start the engine.

2. Turn the blower switch on.

3. Turn the A/C switch on.

4. Check the A/C CLUTCH in the DATA LIST with the HDS.

Does it indicate ON?

YES -

Go to step 5.

NO -

Check the A/C system A/C System Inspection.

5. Check the A/C system operation.

Does the A/C system operate?

YES -

The air conditioning system circuit is OK.

NO -

Go to step 6.

6. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

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

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

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

YES -

Do the A/C system test A/C System Test.

NO -

Go to step 9.

9. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

10. Jump the SCS line with the HDS.

11. Disconnect ECM/PCM connector A (49P).

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

13. Momentarily connect ECM/PCM connector terminal A13 to body ground with a jumper wire several times.





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

YES -

Update the ECM/PCM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away and the ECM/PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair.

NO -

Check for poor connections or loose terminals at the A/C clutch relay and the ECM/PCM. If the connections are OK, check the A/C clutch relay Testing and Inspection. If needed, repair open in the wire between the ECM/PCM (A13) and the A/C clutch relay, and check the other A/C system parts.