Civic L4-1668cc 1.7L SOHC MFI (2003)
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A/C Signal: Testing and Inspection
A/C Signal Circuit Troubleshooting
1. Turn the ignition switch ON (II).
2. Momentarily connect ECM/PCM connector terminals A24 and E18 with a jumper wire several times.
Is there a clicking noise from the A/C compressor clutch?
YES - Go to step 3.
NO - Go to step 6.
3. Start the engine.
4. Turn the blower switch ON.
5. Turn the A/C switch ON.
Does the A/C operate?
YES - The air conditioning signal is OK.
NO - 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.
6. Momentarily connect under-hood fuse/relay box 14P connector terminal No.10 to body ground with a jumper wire several times.
Is there clicking noise from the A/C compressor clutch?
YES - Repair open in the wire between the ECM/PCM (E18) and the A/C clutch relay.
NO - Check the A/C system for other symptoms.