A/C Compressor Clutch Circuit Troubleshooting (Climate Control)

HVAC

A/C Compressor Clutch Circuit Troubleshooting

A/C Compressor Clutch Circuit Troubleshooting

NOTE:
* 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 symptom troubleshooting, check for PGM-FI DTCs How To Troubleshoot The Fuel And Emissions Systems.

1. Fuses check:

Fuses check
-1. Check the following fuses.





Are the fuses OK?
-YES- Go to step 2.
-NO- Replace the fuse(s). If the fuse(s) blows again, repair a short to ground in the No. A25 (7.5 A) fuse and/or the No. B22 (7.5 A) fuse circuit.

2. A/C pressure check:

A/C pressure check
-1. Connect the HDS to the DLC.

-2. Start the engine.

-3. Set the A/C button and the fan control dial to ON.

-4. Using the HDS, check the under following conditions:
* Engine speed between 700 and 800 rpm (K24Z7 engine)
* Engine speed between 620 and 820 rpm (except K24Z7 engine)
* ECT sensor 2 more than 199 °F (93 °C)
* TP sensor about 0.5 V at idle

-5. Using the HDS, confirm the following value in the PGM-FI Data List at idle.





Is the value within specifications?
-YES- Go to step 3.
-NO- Go to the A/C system test result. A/C System Test

3. Climate control system check 2:

Climate control system check 2
-1. Using the HDS, confirm the following values in the PGM-FI Data List at idle.





Are all the values within specifications?
-YES- Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM (K24Z7 engine) Service and Repair or ECM/PCM (except K24Z7 engine) and recheck.
-NO- A/C switch is OFF, go to the A/C signal circuit troubleshooting A/C Signal Circuit Troubleshooting (Climate Control).
-NO- A/C switch is ON and A/C clutch is OFF, go to step 4.

4. A/C compressor clutch relay check:

A/C compressor clutch relay check
-1. Turn the ignition switch to LOCK (0).

-2. Remove the A/C compressor clutch relay from the under-hood fuse/relay box, and test it Testing and Inspection.

Is the relay OK?
-YES- Go to step 5.
-NO- Replace the A/C compressor clutch relay

5. Open wire check (+B_MG_CLUTCH line):

Open wire check (+B_MG_CLUTCH line)
-1. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- The +B_MG_CLUTCH wire is OK. Go to step 6.
-NO- Repair an open in the +B_MG_CLUTCH line.

6. Determine possible failure area (A/C compressor clutch relay switch side circuit, A/C compressor clutch relay coil side circuit):

Determine possible failure area (A/C compressor clutch relay switch side circuit, A/C compressor clutch relay coil side circuit)
-1. Connect terminals A and B with a jumper wire.









Does the A/C compressor clutch click?
-YES- Go to step 7.
-NO- Go to step 9.

7. Open wire check (IG2_A/C line):

Open wire check (IG2_A/C line)
-1. Disconnect the jumper wire.

-2. Turn the ignition switch to ON (II).

-3. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- The IG2_A/C wire is OK. Go to step 8.
-NO- Repair an open or high resistance in the IG2_A/C wire between the under-dash fuse/relay box No. B22 (7.5 A) fuse and the A/C compressor clutch relay.

8. Open wire check (A/C_MG_CLUTCH_RLY_CL- line):

Open wire check (A/C_MG_CLUTCH_RLY_CL- line)
-1. Turn the ignition switch to LOCK (0).

-2. Reinstall the A/C compressor clutch relay.

-3. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the ECM/PCM from damage.

-4. Disconnect the following connector.





-5. Connect terminals A and B with a jumper wire.









-6. Turn the ignition switch to ON (II).

Does the A/C compressor clutch click?
-YES- Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM (K24Z7 engine) Service and Repair or ECM/PCM (except K24Z7 engine) and recheck.
-NO- Repair an open or high resistance in the wire between the A/C compressor clutch relay and the ECM/PCM.

9. Open wire check (A/C_MG_CLUTCH line):

Open wire check (A/C_MG_CLUTCH line)
-1. Disconnect the jumper wire.

-2. Disconnect the following connector.





-3. Check for continuity between test points 1 and 2.

















Is there continuity?
-YES- The A/C_MG_CLUTCH wire is OK. Check the A/C compressor clutch clearance Testing and Inspection and the A/C compressor clutch field coil Service and Repair. Repair as needed.
-NO- Repair an open or high resistance in the wire between the A/C compressor clutch relay and the A/C compressor clutch.