Page 465 of 3383
ATC-64
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
Mode Door Motor CircuitEJS003XO
SYMPTOM:
Air outlet does not change.
Mode door motor does not operate normally.
INSPECTION FLOW
*1AT C - 3 0 , "Discharge Air Flow"*2AT C - 5 8 , "Operational Check
(Front)"
*3 AT C - 5 6 , "A/C System Self-diagnosis
Function"
*4 AT C - 5 7 , "SELF-DIAGNOSIS CODE
CHART"
*5AT C - 6 6 , "DIAGNOSTIC PROCE-
DURE FOR MODE DOOR
MOTOR"
*6 ATC-144, "FRONT AIR CONTROL"
*7 AT C - 3 9 , "SYMPTOM TABLE"
WJIA1970E
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TROUBLE DIAGNOSISATC-65
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Revision: November 2009 2006 QX56
SYSTEM DESCRIPTION
Component Parts
Mode door control system components are:
Front air control
Mode door motor
PBR (built into mode door motor)
In-vehicle sensor
Ambient sensor
Optical sensor
Intake sensor
System Operation
The mode door position (vent, B/L, foot, and defrost) is set by the front air control by means of the mode door
motor. When a mode door position is selected on the front air control, voltage is applied to one circuit of the
mode door motor while ground is applied to the other circuit, causing the mode door motor to rotate. The direc-
tion of rotation is determined by which circuit has voltage applied to it, and which one has ground applied to it.
The front air control monitors the mode door position by measuring the voltage signal on the PBR circuit.
In AUTO mode the mode door position is set by the front air control which determines the proper position
based on inputs from the in-vehicle sensor, ambient sensor, optical sensor, intake sensor, and the temperature
selected by the driver or passenger.
Mode Door Control Specification
WJIA1240E
WJIA0434E
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ATC-66
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
COMPONENT DESCRIPTION
Mode Door Motor
The mode door motor is attached to the heater & cooling unit. It
rotates so that air is discharged from the outlet as indicated by the
front air control. Motor rotation is conveyed to a link which activates
the mode door.
DIAGNOSTIC PROCEDURE FOR MODE DOOR MOTOR
1. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Press the mode switch to the B/L ( ) mode.
3. Check voltage between front air control harness connector M49 terminal 5 and terminal 6 while pressing the mode switch to the
floor ( ) mode.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. CHECK MODE DOOR MOTOR CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 5, 6 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-144, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
WJIA0587E
Connector Terminals
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 6 5 Press
mode
switch Battery
voltage
WJIA1727E
5 - Ground : Continuity should not exist.
6 - Ground : Continuity should not exist.
WJIA1734E
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TROUBLE DIAGNOSISATC-67
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Revision: November 2009 2006 QX56
3. CHECK FRONT AIR CONTROL FOR GROUND AND POWER
1. Press the mode switch to the D/F ( ) mode.
2. Check voltage between front air control harness connector M49 terminal 5 and terminal 6 while pressing the mode switch to the
vent ( ) mode.
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-144, "
FRONT AIR CONTROL" .
4. CHECK MODE DOOR MOTOR AND CIRCUITS FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 5 and terminal 6.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. CHECK MODE DOOR MOTOR CIRCUITS FOR OPEN
1. Disconnect the mode door motor harness connector.
2. Check continuity between front air control harness connector M49 terminal 5, 6 and the mode door motor harness connector
terminal 5, 6.
OK or NG
OK >> Replace mode door motor. Refer to ATC-161, "Removal
and Installation" .
NG >> Repair or replace harness as necessary.
6. CHECK FRONT AIR CONTROL FOR PBR POWER AND GROUND
1. Reconnect front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49 terminal 2 and terminal 15.
OK or NG
OK >> GO TO 8.
NG >> GO TO 7.
Connector Terminals
Condition Voltage
(Approx.)
(+) (-)
Front air control: M49 5 6 Press
mode
switch Battery
voltage
WJIA1742E
Continuity should exist.
WJIA1728E
5 - 5 : Continuity should exist.
6 - 6 : Continuity should exist.
LJIA0027E
Connector Te r m i n a l s
Voltage
(Approx.)
(+) (-)
Front air control: M49 2 15 5V
WJIA1729E
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ATC-68
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
7. CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 2 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-144, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
8. CHECK PBR REFERENCE VOLTAGE AND GROUND CIRCUITS
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 2 and terminal 15.
OK or NG
OK >> GO TO 10.
NG >> GO TO 9.
9. CHECK PBR REFERENCE VOLTAGE CIRCUIT FOR OPEN
1. Disconnect the mode door motor harness connector.
2. Check continuity between mode door motor harness connector M142 (B) terminal 3, 1 and front air control harness connector
M49 (A) terminal 2, 15.
OK or NG
OK >> Replace mode door motor. Refer to ATC-161, "Removal
and Installation" .
NG >> Repair or replace harness as necessary.
10. CHECK PBR FEEDBACK VOLTAGE
1. Reconnect the front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49 terminal 16 and ground while cycling mode switch through all
modes.
OK or NG
OK >> GO TO 12.
NG >> GO TO 11. Continuity should not exist.
WJIA1730E
Continuity should exist.
WJIA1731E
2 - 3
: Continuity should exist.
15 - 1 : Continuity should exist.
WJIA1732E
Voltage : Approx. 1V - 4.5V
LJIA0032E
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TROUBLE DIAGNOSISATC-69
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Revision: November 2009 2006 QX56
11 . CHECK PBR FEEDBACK SIGNAL CIRCUIT FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect front air control harness connector.
3. Check continuity between front air control harness connector M49 terminal 16 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-144, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
12. CHECK PBR FEEDBACK CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the mode door motor harness connector and front air control harness connector.
3. Check continuity between mode door motor harness connector M142 terminal 2 and front air control harness connector M49 ter-
minal 16.
OK or NG
OK >> Replace mode door motor. Refer to ATC-161, "Removal
and Installation" .
NG >> Repair or replace harness as necessary. Continuity should not exist.
WJIA1733E
Continuity should exist.
LJIA0034E
Page 471 of 3383
ATC-70
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
Air Mix Door Motor CircuitEJS003XP
SYMPTOM:
Discharge air temperature does not change.
Air mix door motor does not operate.
INSPECTION FLOW
*1AT C - 5 8 , "Operational Check (Front)"
or ATC-60, "
Operational Check
(Rear)"
*2 AT C - 5 6 , "A/C System Self-diagno-
sis Function"
*3 AT C - 5 7 , "SELF-DIAGNOSIS CODE
CHART"
*4 AT C - 7 2 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (DRIVER)"
*5AT C - 7 6 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (PASSENGER)"
*6 AT C - 7 9 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (REAR)"
WJIA1462E
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TROUBLE DIAGNOSISATC-71
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Revision: November 2009 2006 QX56
SYSTEM DESCRIPTION
Component Parts
Air mix door control system components are:
Front air control.
Air mix door motors (Driver, Passenger, and rear)
PBR (built-into air mix door motors)
In-vehicle sensor
Ambient sensor
Optical sensor
Intake sensor
System Operation
The front air control receives data from the temperature selected by the driver side, passenger side, and rear.
The front air control then applies a voltage to one circuit of the appropriate air mix door motor, while ground is
applied to the other circuit, causing the appropriate air mix door motor to rotate. The direction of rotation is
determined by which circuit has voltage applied to it, and which one has ground applied to it. The front air con-
trol monitors the air mix door positions by measuring the voltage signal on the PBR circuits of each door.
In AUTO mode the air mix, intake, mode door, and defrost door positions are set by the front air control which
determines the proper position based on inputs from the in-vehicle sensor, ambient sensor, optical sensor,
intake sensor, and the temperature selected by the driver and front and rear passengers.
Subsequently, HOT/COLD or DEFROST/VENT or FRESH/RECIRCULATION operation is selected. The new
door position data is returned to the front air control.
Air Mix Door Control Specification
WJIA1244E
WJIA0435E