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ATC-112
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
Rear Air Control CircuitEJS003XU
SYMPTOM:
Temperature cannot be adjusted from the rear air control.
INSPECTION FLOW
*1AT C - 6 0 , "Operational Check
(Rear)"AT C - 6 0 , "Operational Check
(Rear)"
*2AT C - 5 6 , "A/C System Self-diagno-
sis Function"
*3 AT C - 5 7 , "SELF-DIAGNOSIS CODE
CHART"
*4 AT C - 11 3 , "DIAGNOSTIC PROCE-
DURE FOR REAR AIR CONTROL"
*5AT C - 7 9 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (REAR)"
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TROUBLE DIAGNOSISATC-113
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SYSTEM DESCRIPTION
Component Parts
Rear air control system components are:
Front air control
Rear air control
Air mix door motor (rear)
Rear blower motor relay
Rear blower motor resistor
Rear blower motor
System Operation
Rear Air Control
When the rear blower switch (front) (integral to the front air control) is in the REAR position the rear blower
motor speeds and the rear temperature and mode are controlled by the rear blower switch (rear) and the rear
temperature switch (rear) (both integral to the rear air control).
DIAGNOSTIC PROCEDURE FOR REAR AIR CONTROL
SYMPTOM:
Blower motor operation is malfunctioning. Refer to ATC-101, "Rear Blower Motor Circuit" .
Temperature and mode operation is malfunctioning.
1. CHECK OPERATION FROM FRONT AIR CONTROL
Does rear temperature and mode operate normally from front air control?
YES or NO
YES >> GO TO 2.
NO >> Refer to AT C - 7 9 , "
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (REAR)" .
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ATC-114
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
2. CHECK CIRCUIT BETWEEN REAR AIR CONTROL AND FRONT AIR CONTROL FOR OPEN AND
SHORT
1. Turn ignition switch OFF.
2. Disconnect front air control and rear air control connectors.
3. Check continuity between front air control harness connector
M50 terminal 33 and rear air control harness connector R209
terminal 5.
4. Check continuity between rear air control harness connector R209 terminal 5 and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3. CHECK CIRCUIT BETWEEN REAR AIR CONTROL AND AIR MIX DOOR MOTOR (REAR) FOR OPEN
OR SHORT
1. Disconnect air mix door motor (rear) connector.
2. Check continuity between rear air control harness connector R209 terminal 2 and 4 and air mix door motor (rear) harness
connector B155 terminal 2 and 3.
3. Check continuity between rear air control harness connector R209 terminals 2 and 4 and ground.
OK or NG
OK >> Replace rear air control.
NG >> Repair harness or connector. 33 - 5
Continuity should exist.
5 - Ground Continuity should not exist.
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2 - 2Continuity should exist.
4 - 3 Continuity should exist.
2, 4 - Ground Continuity should not exist.
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TROUBLE DIAGNOSISATC-115
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Magnet Clutch CircuitEJS003XV
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
*1 .ATC-58, "Operational Check
(Front)"
*2ATC-56, "A/C System Self-diagnosis
Function"
*3 AT C - 5 7 , "SELF-DIAGNOSIS CODE
CHART"
*4ATC-134, "Ambient Sensor Circuit"*5ATC-142, "Intake Sensor Circuit"
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ATC-116
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
SYSTEM DESCRIPTION
The front air control controls compressor operation based on ambient and intake temperature and a signal
from ECM.
Low Temperature Protection Control
The front air control will turn the compressor ON or OFF as determined by a signal detected by the intake sen-
sor and the ambient sensor.
When intake air temperature is higher than the preset value, the compressor turns ON. The compressor turns
OFF when intake air temperature is lower than the preset value. That preset value is dependent on the ambi-
ent temperature, refer to the following table.
DIAGNOSTIC PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
1. CHECK INTAKE AND AMBIENT SENSOR CIRCUITS
Check intake and ambient sensors. Refer to AT C - 5 6 , "
A/C System Self-diagnosis Function" .
OK or NG
OK >> GO TO 2.
NG >>
Malfunctioning intake sensor. Refer to ATC-142, "Intake Sensor Circuit" .
Malfunctioning ambient sensor. Refer to ATC-142, "Intake Sensor Circuit" .
Ambient temperature °C (°F)C om pr esso r ON
intake temperature °C ( °F)C o m p r e s s o r O F F
intake temperature ° C (°F)
0 (32) 2.5 (37) 2.0 (36)
10 (50) 2.5 (37) 2.0 (36)
20 (68) 2.5 (37) 1.5 (35)
30 (86) 2.0 (36) 0.5 (33)
40 (104) 2.0 (36)0.5 (33)
50 (122) 2.0 (36)0.5 (33)
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TROUBLE DIAGNOSISATC-117
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2. PERFORM AUTO ACTIVE TEST
Refer to PG-24, "
Auto Active Test" .
Does magnet clutch operate?
YES or NO
YES >>WITH CONSULT-II
GO TO 5.
WITHOUT CONSULT-II
GO TO 6.
NO >> Check 10A fuse (No. 42, 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 (magnet clutch) connector.
3. Check continuity between IPDM E/R harness connector E119 terminal 11 and compressor harness connector F3 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 >> Replace IPDM E/R. Refer to PG-30, "Removal and
Installation of IPDM E/R" .
NG >> Replace magnet clutch. Refer to ATC-176, "
Removal
and Installation for Compressor Clutch" .
5. CHECK BCM INPUT (COMPRESSOR ON) SIGNAL
Check compressor ON/OFF signal. Refer to AT C - 3 4 , "
CONSULT-II
Function (HVAC)" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.
11 – 1 : Continuity should exist.
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A/C SW ON : COMP ON SIG ON
A/C SW OFF : COMP ON SIG OFF
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ATC-118
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
6. CHECK CIRCUIT CONTINUITY BETWEEN BCM AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect BCM connector and front air control connector.
3. Check continuity between BCM harness connector M18 terminal 27 and front air control harness connector M49 terminal 12.
OK or NG
OK >> GO TO 7.
NG >> Repair harness or connector.
7. CHECK VOLTAGE FOR FRONT AIR CONTROL (COMPRESSOR ON SIGNAL)
1. Reconnect BCM connector and front air control connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49 terminal 12 and ground.
OK or NG
OK >> GO TO 8.
NG-1 >> If the voltage is approx. 5V when A/C switch is ON, replace front air control. Refer to ATC-144,
"FRONT AIR CONTROL" .
NG-2 >> If the voltage is approx. 0V when A/C switch is OFF, replace BCM. Refer to BCS-20, "
BCM" .
8. CHECK REFRIGERANT PRESSURE SENSOR
WITH CONSULT-II
1. Start engine.
2. Check voltage of refrigerant pressure sensor. Refer to AT C - 3 4 , "
CONSULT-II Function (HVAC)" .
WITHOUT CONSULT-II
1. Start engine.
2. Check voltage between ECM harness connector F54 terminal 70 and ground.
OK or NG
OK >>WITH CONSULT-II
GO TO 9.
WITHOUT CONSULT-II
GO TO 10.
NG >> Refer to EC-630, "
REFRIGERANT PRESSURE SENSOR" .
27 - 12 Continuity should exist.
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Terminals
Condition Voltage
(+)
(-)
Front air
control con-
nector Terminal No.
M49 12 Ground A/C switch: ON Approx. 0V
A/C switch: OFF Approx. 5V
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Te r m i n a l s
ConditionVoltage
(+)
(-)
ECM con-
nector Terminal No.
F54 70 Ground A/C switch: ON Approx. 0.36 - 3.88V
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9. CHECK BCM INPUT (FAN ON) SIGNAL
Check FAN ON/OFF signal. Refer to AT C - 3 4 , "
CONSULT-II Function
(HVAC)" .
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
10. CHECK CIRCUIT CONTINUITY BETWEEN BCM AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect BCM connector and front air control connector.
3. Check continuity between BCM harness connector M18 terminal 28 and front air control harness connector M49 terminal 10.
OK or NG
OK >> GO TO 11.
NG >> Repair harness or connector.
11 . CHECK VOLTAGE FOR FRONT AIR CONTROL (FAN ON SIGNAL)
1. Reconnect BCM connector and front air control connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49 terminal 10 and ground.
OK or NG
OK >> GO TO 12.
NG-1 >> If the voltage is approx. 5V when blower motor is ON, replace front air control. Refer to ATC-144,
"FRONT AIR CONTROL" .
NG-2 >> If the voltage is approx. 0V when blower motor is OFF, replace BCM. Refer to BCS-20, "
BCM" .
FRONT BLOWER CONTROL
DIAL ON
: FAN ON SIG ON
FRONT BLOWER CONTROL
DIAL OFF : FAN ON SIG OFF
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28 - 10
Continuity should exist.
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Terminals
Condition Voltage
(+)
(-)
Front air con-
trol connector Terminal No.
M49 10GroundA/C switch: ON
Blower motor
operates
Approx. 0V
A/C switch: OFF Approx. 5V
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