A/C Compressor Clutch Circuit Troubleshooting
- 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 refrigerant 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 ). Also check for B-CAN codes (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).
- Check the No. A21 (7.5 A) fuse in the under-hood fuse/relay box, and the No. B16 (7.5 A) fuse in the driver's 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. A21 (7.5 A) fuse and the No. B16 (7.5 A) fuse circuits.
- Connect the HDS to the DLC (see HOW TO CHECK FOR DTCS WITH THE HDS ).
- Start the engine.
- Turn on the A/C.
- Check the A/C switch in the PGM-FI Data List with the HDS.
Is the A/C switch on?
YES -Go to step 6.
NO -Go to A/C SIGNAL CIRCUIT TROUBLESHOOTING .
- Using the HDS, confirm the following values in the PGM-FI Data List at idle.PGM-FI DATA LIST
TP SENSOR About 0.5 V RPM 650-750 ECT SENSOR 2 176-212 °F (80-100 °C) A/C SWITCH ON A/C CLUTCH 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.
- Turn the ignition switch to LOCK (0).
- Remove the A/C compressor clutch relay from the under-hood fuse/relay box, 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 REMOVAL AND INSTALLATION ).
- Connect A/C compressor clutch relay 4P socket terminal No. 1 and No. 2 with a 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. 3 and body ground.Fig 3: Measuring Voltage Between A/C Compressor Clutch Relay 4P Socket Terminal No. 3 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. B16 (7.5 A) fuse in the driver's 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.
- Turn the ignition switch to ON (II).
Does the A/C compressor clutch 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.