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, or hard acceleration.
- 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. B10 (7.5 A) and the No. B43 (7.5 A) fuse in the under-dash fuse/relay box.
Are the fuses OK?
YES -Go to step 2.
NO -Replace the fuse, and recheck. If the fuses blow again, check for a short in the No. B10 (7.5 A) and No. B43 (7.5 A) fuse circuits.
- Connect the HDS to the DLC.
- 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 7.
NO -Go to step 6.
- Using the HDS, confirm the following values in the PGM-FI Data List at idle.PGM-FI DATA LIST REFERENCE
TP sensor About 0.5 V at idle RPM 700-800 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 auxiliary under-hood relay box A, 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. 7 and body ground.Fig 1: Measuring Voltage Between A/C Compressor Clutch Relay 4P Socket Terminal No. 7 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES -Go to step 10.
NO -Repair an open in the wire between the No. B43 (7.5 A) fuse in the under-dash fuse/relay box and the A/C compressor clutch relay.
- Connect A/C compressor clutch relay 4P socket terminals No. 7 and No. 8 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 22.
- Disconnect the jumper wire.
- Turn the ignition switch to ON (II).
- Measure the voltage between A/C compressor clutch relay 4P socket terminal No. 16 and body ground.Fig 3: Measuring Voltage Between A/C Compressor Clutch Relay 4P Socket Terminal No. 16 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. B10 (7.5 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.
- Make sure the A/C switch is OFF.
- Jump the SCS line with the HDS.NOTE: This step must be done to protect the engine control module (ECM)/powertrain control module (PCM) from damage.
- Disconnect ECM/PCM connector A (44P).
- Measure the voltage between ECM/PCM connector A (44P) terminal No. 14 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there 0.5 V or less?
YES -Faulty A/C compressor clutch relay or short to power on the BLU wire. Repair the faulty part or repair the short, then replace the ECM/PCM (see ECM/PCM REPLACEMENT ).
NO -Go to step 20.
- Connect ECM/PCM connector A (44P) terminal No. 14 to body ground with a jumper wire.
- Turn the ignition switch to ON (II).
Does the A/C compressor click?
YES -Check for loose wires or poor connections at ECM/PCM connector A (44P). If the connections are good, substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), and recheck. If the symptom/indication goes away, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).
NO -Repair an open in the wire between the A/C compressor clutch relay and the ECM/PCM.
- Disconnect the jumper wire.
- Disconnect the A/C compressor clutch 3P connector.
- Check for continuity between A/C compressor clutch relay 4P socket terminal No. 8 and A/C compressor clutch 3P connector terminal No. 2.Fig 6: Checking Continuity Between A/C Compressor Clutch Relay 4P Socket Terminal No. 8 And A/C Compressor Clutch 3P Connector Terminal No. 2
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Check the A/C compressor clutch clearance, the thermal protector circuit, and the A/C compressor clutch field coil.
NO -Repair an open in the wire between the A/C compressor clutch relay and the A/C compressor clutch.