A/C Signal Circuit Troubleshooting
- Start the engine.
- Turn the blower switch on.
- Turn the A/C switch on.
- 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 pressure sensor circuit troubleshooting (see DTC B2979 OR PRE SENSOR OPEN IS INDICATED: AN OPEN IN THE A/C PRESSURE SENSOR CIRCUIT ).
- Check the A/C system.
Does the A/C system operate?
YES - The air conditioning system circuit is OK.
NO - Go to step 6.
- Turn the ignition switch to LOCK (0).
- Turn the ignition switch to ON (II).
- 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 A/C SYSTEM TEST .
NO - Go to step 9.
- Momentarily connect PCM connector terminal E27 to body ground with a jumper wire several times.
Is there a clicking noise from the A/C compressor clutch?
YES - Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM (see PCM REPLACEMENT ).
NO - Check for poor connections or loose terminals at the A/C compressor clutch relay in the under-hood fuse/relay box and the PCM. If the connections are OK, check the A/C compressor clutch relay (see POWER RELAY TEST ), repair open in the wire between the PCM (E27) and the A/C compressor clutch relay.