A/C Signal Circuit Troubleshooting

WARNING: This page is about a different car, the 2008 Honda Pilot, 2007 Honda Pilot, and 2006 Honda Pilot. However, it is still accessible from the selected car via links, so may be relevant.

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 Switch Circuit Troubleshooting (see A/C PRESSURE SWITCH CIRCUIT TROUBLESHOOTING ).
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 OFF.
Turn the ignition switch 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 the A/C System Test (see A/C SYSTEM TEST ).

NO - Go to step 9.
Turn the ignition switch OFF.
Jump the SCS line with the HDS.
Disconnect PCM connector A (44P).
Turn the ignition switch ON (II).
Momentarily connect PCM connector terminal A14 to body ground with a jumper wire several times.

Fig 1: Connecting PCM Connector Terminal A14 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.

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 UPDATING AND SUBSTITUTION FOR TESTING ), or substitute a known-good PCM (see HOW TO SUBSTITUTE 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 clutch relay and the PCM. If the connections are OK, check the A/C clutch relay (see POWER RELAY TEST ), repair open in the wire between the PCM (A14) and the A/C clutch relay and the other A/C systems.