Civic L4-1.8L (2006)
A/C Signal: Testing and Inspection
A/C Signal Circuit Troubleshooting
1. Start the engine, and let it idle.
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 - Do the A/C system test.
5. Check the A/C system.
Does the A/C system operate?
Yes - The air conditioning system circuit is OK.
NO - Go to step 6.
6. Turn the ignition switch OFF.
7. Turn the ignition switch ON (II).
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.
NO - Go to step 9.
9. Turn the ignition switch OFF.
10. Jump the SCS line with the HDS.
11. Disconnect ECM/PCM connector A (44P).
12. Turn the ignition switch ON (II).
13. Momentarily connect ECM/PCM connector terminal A14 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, or substitute a known-good ECM/PCM, then recheck. If the
symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.
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, repair open in the wire between the ECM/PCM (A14) and the A/C clutch relay and the other A/C systems.
