A/C Signal Circuit Troubleshooting

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. 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 -Check the A/C system (see GENERAL TROUBLESHOOTING INFORMATION ).
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.
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 the A/C system test (see A/C SYSTEM TEST ).

NO -Go to step 9.
Turn the ignition switch to LOCK (0).
Jump the SCS line with the HDS.
Disconnect PCM connector A (49P).
Turn the ignition switch to ON (II).
Momentarily connect PCM connector terminal A13 to body ground with a jumper wire several times.

Fig 1: Connecting PCM Connector Terminal A13 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 KNOCK SENSOR REPLACEMENT ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ).

NO -Check for poor connections or loose terminals at the A/C compressor clutch relay and the PCM. If the connections are OK, check the A/C compressor clutch relay (see POWER RELAY TEST ). If needed, repair an open in the wire between the PCM (A13) and the A/C compressor clutch relay and the other A/C system parts.