Automatic Air Conditioning
MAGNET CLUTCH
Description
SYSTEM DESCRIPTION
When the blower speed dial is in one of the fan speed positions, the front air control outputs a fan ON signal to the BCM. When the A/C switch is pressed, the A/C switch LED illuminates and the front air control outputs a compressor ON signal to the BCM. Any mode control button can be selected. The front air control also monitors the intake sensor for low temperature. As long as the BCM receives a compressor ON signal and a fan
ON signal from the front air control, the conditions required for the BCM to transmit a compressor ON request to the ECM have been met.
The BCM sends a compressor ON signal to ECM, via CAN communication line.
The ECM judges whether the compressor can be turned ON, based on each sensor status (refrigerant pressure sensor signal, throttle angle sensor, etc.). If it judges the compressor can be turned ON, it sends a compressor ON signal to IPDM E/R, via CAN communication line.
Upon receipt of a compressor ON signal from ECM, IPDM E/R turns the A/C relay ON to operate the compressor.
Low Temperature Protection Control
The IPDM E/R will turn the compressor ON or OFF as determined by a signal detected from the ambient temperature sensor. The front air control monitors the ambient temperature sensor, and based on the threshold temperatures will stop sending the compressor ON signal to the BCM.
When ambient temperature is greater than -2�C (28�F), the A/C compressor turns ON. The A/C compressor turns OFF when ambient temperature is less than -5�
C (23�F).
Component Function Check
INSPECTION FLOW
1. CONFIRM SYMPTOM BY PERFORMING OPERATION CHECK - MAGNET CLUTCH
1.Start engine.
2.Press the VENT () mode.
3.Press A/C switch.
4.Confirm that the A/C compressor clutch engages (sound or visual inspection).
Is the inspection result normal?
YES- Inspection End.
NO- Perform diagnosis procedure to Magnet Clutch. Refer to "Diagnosis Procedure".
Diagnosis Procedure
Regarding Wiring Diagram information, Coupe or Sedan.
DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
1. CHECK MAGNETIC CLUTCH WITH AUTO ACTIVE TEST
1.Perform auto active test. Diagnosis Description.
2.Check that the A/C compressor clutch operates.
Does the A/C compressor clutch operate?
YES- GO TO 2
NO- GO TO 3
2. DATA MONITOR
1.Press ignition switch ON.
2.With CONSULT, select "ENGINE", then "DATA MONITOR" mode.
3.Select "AIR COND SIG" and monitor while pressing A/C switch ON and OFF.
Is the inspection result normal?
YES- Check refrigerant pressure sensor. Refrigerant Pressure Sensor (QR25DE for California) or Refrigerant Pressure Sensor (QR25DE for except for California) Refrigerant Pressure Sensor (VQ35DE).
NO- GO TO 6
3. CHECK POWER SUPPLY FOR A/C COMPRESSOR
1.Disconnect A/C compressor connector.
2.Start engine and press A/C switch.
3.Check voltage between A/C compressor harness connector F3 terminal 1 and ground.
Is the inspection result normal?
YES-Check magnet clutch coil.
1.If NG, replace magnet clutch. Service and Repair or Service and Repair.
2.If OK, check A/C compressor ground circuit and repair as necessary.
NO- GO TO 4
4. CHECK CIRCUIT CONTINUITY BETWEEN A/C RELAY IN IPDM E/R AND A/C COMPRESSOR
1.Disconnect IPDM E/R connector F10.
2.Check continuity between A/C compressor harness connector
F3 (A) terminal 1 and IPDM E/R harness connector F10 (B) terminal 48.
If OK, check harness for short to ground.
Is the inspection result normal?
YES- GO TO 5
NO- Repair harness or connector.
5. CHECK FUSE IN IPDM E/R
Check 10A fuse (No. 41 located in the IPDM E/R).
Is the inspection result normal?
YES- Replace IPDM E/R. Service and Repair.
NO- Replace fuse and check IPDM E/R for short circuit. Replace if necessary.
6. CHECK A/C COMPRESSOR ON SIGNAL
Check voltage between front air control connector M152 terminal 5 and ground, with A/C compressor ON and with A/C compressor
OFF.
Is the inspection result normal?
YES- GO TO 8
NO- GO TO 7
7. CHECK CONTINUITY BETWEEN BCM AND FRONT AIR CONTROL
1.Disconnect BCM connector M18 and front air control connector.
2.Check continuity between BCM harness connector M18 terminal 33 and front air control connector M152 terminal 5.
3.Check continuity between BCM harness connector M18 terminal 33 and ground.
Is the inspection result normal?
YES- Replace BCM. Service and Repair.
NO- Repair harness or connector.
8. CHECK CAN COMMUNICATION CIRCUITS
Check CAN communication circuits between BCM to ECM and between ECM to IPDM E/R. Scan Tool Testing and Procedures.
Is the inspection result normal?
YES- BCM malfunctioning.
NO- Repair or replace component based on the result of diagnosis.