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TROUBLE DIAGNOSIS ATC-83
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Revision: 2006 December 2006 FX35/FX45
SYSTEM DESCRIPTION
Unified meter and A/C amp. controls compressor operation by ambient temperature, intake air temperature
and signal from ECM.
Low Temperature Protection Control
Unified meter and A/C amp. will turn the compressor ON or OFF as determined by a signal detected by ambi-
ent sensor and intake sensor.
When ambient temperature is higher than −2 °C (28 °F), the compres-
sor turns ON. The compressor turns OFF when ambient temperature
is lower than −5 °C (23 °F).
When intake air temperature is higher than 1 °C (34 °F), the compres-
sor turns ON. The compressor turns OFF when intake air tempera-
ture is lower than −5°C (23 °F).
DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
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ATC-84
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
1. CHECK AMBIENT SENSOR AND INTAKE SENSOR CIRCUIT
Check ambient sensor and intake sensor. Refer to AT C - 5 3 , "
FUNCTION CONFIRMATION PROCEDURE" ,
see No. 9 and 11.
OK or NG
OK >> GO TO 2.
NG >>
Malfunctioning ambient sensor: Refer to ATC-103, "Ambient Sensor Circuit" .
Malfunctioning intake sensor: Refer to AT C - 11 2 , "Intake Sensor Circuit" .
2. PERFORM AUTO ACTIVE TEST
Refer to PG-21, "
Auto Active Test" .
Does the magnet clutch operate?
YES >>WITH CONSULT-II: GO TO 5
WITHOUT CONSULT-II: GO TO 6.
NO >> Check 10A fuse (No. 79, located in IPDM E/R), and GO TO 3.
3. CHECK CIRCUIT CONTINUITY BETWEEN IPDM E/R AND COMPRESSOR
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R connector and compressor connector.
3. Check continuity between IPDM E/R harness connector E8 ter- minal 33 and compressor harness connector F2 terminal 1.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK MAGNET CLUTCH CIRCUIT
Check for operation sound when applying battery voltage direct cur-
rent to terminal.
OK or NG
OK >> 1. Replace IPDM E/R.
2. Go to self-diagnosis procedure AT C - 5 3 , "
FUNCTION
CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-4. Confirm that magnet clutch opera-
tion normal.
NG >> 1. Replace magnet clutch. Refer to ATC-142, "
Removal
and Installation of Compressor Clutch" .
2. Go to self-diagnosis procedure AT C - 5 3 , "
FUNCTION
CONFIRMATION PROCEDURE" and perform self-diagnosis STEP-4. Confirm that magnet
clutch operation normal.
33 – 1 : Continuity should exist.
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TROUBLE DIAGNOSIS ATC-85
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Revision: 2006 December 2006 FX35/FX45
5. CHECK BCM INPUT (COMPRESSOR ON) SIGNAL
Check compressor ON/OFF signal. Refer to AT C - 4 0 , "
CONSULT-II
Function (BCM)" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.
6. CHECK CIRCUIT CONTINUITY BETWEEN BCM AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect BCM connector and unified meter and A/C amp. connector.
3. Check continuity between BCM harness connector M3 terminal 27 and unified meter and A/C amp. harness connector M57 ter-
minal 42.
OK or NG
OK >> GO TO 7.
NG >> Repair harness or connector. A/C SW ON : AIR COND SW ON
A/C SW OFF : AIR COND SW OFF
R J I A 1111 E
27 – 42 : Continuity should exist.
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ATC-86
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
7. CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (COMPRESSOR ON SIGNAL)
1. Reconnect BCM connector and unified meter and A/C amp. connector.
2. Turn ignition switch ON.
3. Check voltage between unified meter and A/C amp. harness connector M57 terminal 42 and ground using an oscilloscope.
OK or NG
OK >> GO TO 8.
NG-1 >> If the voltage is approx. 5 V when A/C switch is ON: Replace unified meter and A/C amp.
NG-2 >> If the voltage is approx. 0 V when A/C switch is OFF: Replace BCM.
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Terminals
Condition Voltage
(+)
( − )
Unified meter
and A/C amp. connector Terminal
No.
M57 42 Ground A/C switch: ON
(Blower motor operates.) Approx. 0 V
OFF switch: ON
(A/C system: OFF)
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TROUBLE DIAGNOSIS ATC-87
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8. CHECK REFRIGERANT PRESSURE SENSOR
WITH CONSULT-II
1. Start the engine.
2. Check voltage of refrigerant pressure sensor. Refer to EC-133, "
CONSULT-II Reference Value in Data
Monitor" (VQ35DE) or EC-795, "CONSULT-II Reference Value in Data Monitor" (VK45DE).
WITHOUT CONSULT-II
1. Start the engine.
2. Check voltage between ECM harness connector F101 terminal 70 and ground.
OK or NG
OK >>WITH CONSULT-II: GO TO 9.
WITHOUT CONSULT-II: GO TO 10.
NG >> Refer to EC-662, "
REFRIGERANT PRESSURE SENSOR" (VQ35DE) or EC-1341, "REFRIGER-
ANT PRESSURE SENSOR" (VK45DE).
9. CHECK BCM INPUT (FAN ON) SIGNAL
Check FAN ON/OFF signal. Refer to AT C - 4 0 , "
CONSULT-II Function
(BCM)" .
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
10. CHECK CIRCUIT CONTINUITY BETWEEN BCM AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect BCM connector and unified meter and A/C amp. connector.
3. Check continuity between BCM harness connector M3 terminal 28 and unified meter and A/C amp. harness connector M57 ter-
minal 57.
OK or NG
OK >> GO TO 11.
NG >> Repair harness or connector.
Terminals
Condition Voltage
(+)
( − )
ECM
connec-
tor Terminal
No.
F101 70 Ground A/C switch: ON
(Blower motor operates.) Approx. 1.0 - 4.0
V
PBIB1188E
FAN SW ON : FAN ON SIG ON
FAN SW OFF : FAN ON SIG OFF
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28 – 57 : Continuity should exist.
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ATC-88
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
11 . CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (FAN ON SIGNAL)
1. Reconnect BCM connector and unified meter and A/C amp. connector.
2. Turn ignition switch ON.
3. Check voltage between unified meter and A/C amp. harness connector M57 terminal 57 and ground using an oscilloscope.
OK or NG
OK >> GO TO 12.
NG-1 >> If the voltage is approx. 5 V when blower motor is ON: Replace unified meter and A/C amp.
NG-2 >> If the voltage is approx. 0 V when blower motor is OFF: Replace BCM. Refer to BCS-15,
"Removal and Installation of BCM" .
12. CHECK CAN COMMUNICATION
Check CAN communication. Refer to BCS-14, "
CAN Communication Inspection Using CONSULT-II (Self-
Diagnosis)" .
BCM – ECM
ECM – IPDM E/R
ECM – Unified meter and A/C amp.
OK or NG
OK >> Replace ECM
NG >> Repair or replace malfunctioning part(s).
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Terminals
Condition Voltage
(+)
(-)
Unified meter
and A/C amp. connector Terminal No.
M57 57 Ground A/C switch: ON
(Blower motor operates.) Approx. 0 V
OFF switch: ON
(A/C system: OFF)
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TROUBLE DIAGNOSIS ATC-89
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Revision: 2006 December 2006 FX35/FX45
COMPONENT INSPECTION
Refrigerant Pressure Sensor
The refrigerant pressure sensor is attached to the condenser.
Make sure that the A/C refrigerant pressure and the sensor output
voltage are within the specified range as shown in the A/C operating
condition figure. Refer to EC-662, "
REFRIGERANT PRESSURE
SENSOR" (VQ35DE) or EC-1341, "REFRIGERANT PRESSURE
SENSOR" (VK45DE).
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ATC-90
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
Insufficient CoolingNJS000EA
SYMPTOM: Insufficient cooling
INSPECTION FLOW
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