A/C Compressor Clutch 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.

NOTE:

It is normal for the A/C compressor to turn off under certain conditions, such as low idle, high engine coolant temperature, hard acceleration, or high/low pressure.
Do not use this troubleshooting procedure if the fans are also inoperative with the A/C on. Refer to the SYMPTOM TROUBLESHOOTING INDEX .
Before doing any symptom troubleshooting, check for powertrain DTCs (see GENERAL TROUBLESHOOTING INFORMATION ).

Check the No. 17 (7.5 A) fuse in the relay block, and the No. 30 (10 A) fuse in the under-dash fuse/relay box.
Are the fuses OK?

YES -Go to step 2.

NO -Replace the fuse(s) and recheck. If the fuse(s) blow again, check for a short in the No. 17 (7.5 A) and No. 30 (10 A) fuse(s) circuit.
Connect the HDS to the DLC.
Start the engine.
Turn on the A/C.
Check the A/C CLUTCH in the PGM-FI Data List with the HDS.
Is the A/C CLUTCH on?

YES -Go to step 7.

NO -Go to step 6.

Using the HDS, confirm the following values in the PGM-FI Data List at idle.

A/C SWITCH	ON
A/C PRESSURE SENSOR	196-3, 138 kPa (2.00-32.00 kgf/cm² ) [28.4-455.1 psi]

Are all the values within specifications?

YES -Go to step 7.

NO -Troubleshoot the value that is not within the specifications.

Set the A/C button and fan control button OFF, then turn the ignition switch to LOCK (0).
Remove the A/C compressor clutch relay from the relay block, and test it (see POWER RELAY TEST ).
Is the relay OK?

YES -Go to step 9.

NO -Replace the A/C compressor clutch relay.
Measure the voltage between A/C compressor clutch relay 4P socket terminal No. 1 and body ground.

Fig 1: Measuring Voltage Between A/C Compressor Clutch Relay 4P Socket Terminal No. 1 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 10.

NO -Replace the under-hood fuse/relay box (see DTC B1065: RELAY CONTROL MODULE LOST COMMUNICATION WITH DRIVER'S MPCS UNIT (DRLOCKSW MESSAGE) ).
Connect A/C compressor clutch relay 4P socket terminals No. 1 and No. 2 with a jumper wire.

Fig 2: Connecting A/C Compressor Clutch Relay 4P Socket Terminals No. 1 And No. 2 With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Does the A/C compressor clutch click?

YES -Go to step 11.

NO -Go to step 20.
Disconnect the jumper wire.
Turn the ignition switch to ON (II).
Measure the voltage between A/C compressor clutch relay 4P socket terminal No. 4 and body ground.

Fig 3: Measuring Voltage Between A/C Compressor Clutch Relay 4P Socket Terminal No. 4 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 14.

NO -Repair an open in the wire between the No. 30 (10 A) fuse in the under-dash fuse/relay box and the A/C compressor clutch relay.
Turn the ignition switch to LOCK (0).
Reinstall the A/C compressor clutch relay.
Jump the SCS line with the HDS.
NOTE: This step must be done to protect the powertrain control module (PCM) from damage.
Disconnect PCM connector A (49P).
Connect PCM connector A (49P) terminal No. 13 to body ground with a jumper wire.

Fig 4: Connecting PCM Connector A (49P) Terminal No. 13 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to ON (II).
Does the A/C compressor click?

YES -Check for loose wires or poor connections at PCM connector A (49P). If the connections are good, check the PCM grounds. If the grounds are good, substitute a known-good PCM (see SUBSTITUTING THE PCM ), and recheck. If the symptom/indication goes away, replace the original PCM (see PCM REPLACEMENT ).

NO -Repair an open in the wire between the A/C compressor clutch relay and the PCM.
Disconnect the jumper wire.
Disconnect the A/C compressor clutch 1P connector.
Check for continuity between A/C compressor clutch relay 4P socket terminal No. 2 and A/C compressor clutch 1P connector terminal No. 1.

Fig 5: Checking For Continuity Between A/C Compressor Clutch Relay 4P Socket Terminal No. 2 And A/C Compressor Clutch 1P Connector Terminal No. 1
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Check the A/C compressor clutch clearance, and the A/C compressor clutch field coil (see A/C COMPRESSOR CLUTCH CHECK ). Repair as needed.

NO -Repair an open in the wire between the A/C compressor clutch relay and the A/C compressor clutch.