INFINITI QX56 2004 Factory Service Manual

ATC-66
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
4. CHECK PBR REFERENCE VOLTAGE CIRCUIT BETWEEN MODE DOOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between mode door motor harness connector
M142 terminal 3 (Y) and front air control harness connector M49
terminal 2 (Y).
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
5. CHECK PBR GROUND REFERENCE CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between mode door motor harness connector
M142 terminal 1 (P) and front air control harness connector M49
terminal 15 (P).
OK or NG
OK >> GO TO 6.
NG >> Repair or replace harness as necessary.
6. CHECK PBR FEEDBACK SIGNAL
1. Reconnect front air control connector and mode door motor connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49
terminal 16 (GR) and ground.
4. Press mode switch through all modes.
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL" .
NG >> GO TO 7.
7. CHECK PBR FEEDBACK CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect mode door motor connector M142 and front air con-
trol harness connector M49.
3. Check continuity between mode door motor harness connector
M142 terminal 2 (GR) and front air control harness connector
M49 terminal 16 (GR).
OK or NG
OK >> Replace mode door motor. Refer to ATC-152, "MODE
DOOR MOTOR" .
NG >> Repair or replace harness as necessary.3 - 2 : Continuity should exist.
LJIA0029E
1 - 15 : Continuity should exist.
LJIA0031E
16 - Ground : Approx. 0 - 5V
LJIA0032E
2 - 16 : Continuity should exist.
LJIA0034E

TROUBLE DIAGNOSIS
ATC-67
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
Air Mix Door Motor CircuitEJS002CF
SYMPTOM:

Discharge air temperature does not change.

Air mix door motor does not operate.
INSPECTION FLOW
*1ATC-56, "Operational Check (Front)"
or AT C - 5 9 , "
Operational Check
(Rear)"
*2AT C - 5 3 , "A/C System Self-diagno-
sis Function"
*3AT C - 5 5 , "SELF-DIAGNOSIS CODE
CHART"
*4ATC-69, "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (DRIVER)"
*5AT C - 7 1 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (PASSENGER)"
*6AT C - 7 3 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (REAR)"
WJIA0768E

ATC-68
TROUBLE DIAGNOSIS
Revision: August 20072004 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
WJIA0427E
WJIA0435E

TROUBLE DIAGNOSIS
ATC-69
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
COMPONENT DESCRIPTION
Air Mix Door Motors
The driver and front passenger air mix door motors are attached to
the front heater & cooling unit. The rear air mix door motor is
attached to the rear heater & cooling unit. These motors rotate so
that the air mix door is opened or closed to a position set by the front
(or rear) air control. Motor rotation is then conveyed through a shaft
and the air mix door position is then fed back to the front air control
by the PBR built into the air mix door motors.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (DRIVER)
1. CHECK RESULT FROM FRONT AIR CONTROL SELF-DIAGNOSIS
Self-diagnosis code 22 is present. Refer to ATC-53, "
A/C System Self-diagnosis Function" .
YES or NO
YES >> GO TO 2.
NO >> GO TO 3.
WJIA0546E
WJIA0547E
WJIA0894E

ATC-70
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
2. CHECK POWER SUPPLY CIRCUITS FOR AIR MIX DOOR MOTOR (DRIVER)
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49 and air mix door
motor (Driver) connector M147.
3. Check continuity between front air control harness connector
M49 terminal 3 (W/G) and 4 (G) and air mix door motor (Driver)
harness connector M147 terminal 1 (W/G) and 6 (G).
OK or NG
OK >> Replace air mix door motor (Driver). Refer to ATC-153,
"FRONT AIR MIX DOOR MOTOR (DRIVER)" .
NG >> Repair or replace harness as necessary.
3. CHECK PBR REFERENCE SIGNAL VOLTAGE
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (Driver) connector M147.
3. Turn ignition switch ON.
4. Check voltage between air mix door motor (Driver) harness con-
nector M147 terminal 3 (Y) and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4. CHECK PBR REFERENCE VOLTAGE CIRCUIT BETWEEN AIR MIX DOOR MOTOR (DRIVER) AND
FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between air mix door motor (Driver) harness
connector M147 terminal 3 (Y) and front air control harness con-
nector M49 terminal 2 (Y).
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
5. CHECK PBR GROUND REFERENCE CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between air mix door motor (Driver) harness
connector M147 terminal 2 (P) and front air control harness con-
nector M49 terminal 15 (P).
OK or NG
OK >> GO TO 6.
NG >> Repair or replace harness as necessary.3 - 1 : Continuity should exist.
4 - 6 : Continuity should exist.
WJIA0588E
3 - Ground : Approx. 5V
LJIA0038E
3 - 2 : Continuity should exist.
LJIA0039E
2 - 15 : Continuity should exist.
WJIA0589E

TROUBLE DIAGNOSIS
ATC-71
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
6. CHECK PBR FEEDBACK SIGNAL
1. Reconnect front air control connector and air mix door motor
(Driver) connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49
terminal 18 (SB) and ground.
4. Rotate temperature dial (Driver) through complete range.
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL" .
NG >> GO TO 7.
7. CHECK PBR FEEDBACK CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (Driver) connector M147 and
front air control connector M49.
3. Check continuity between air mix door motor (Driver) harness
connector M147 terminal 4 (SB) and front air control harness
connector M49 terminal 18 (SB).
OK or NG
OK >> Replace air mix door motor (Driver). Refer to ATC-153,
"FRONT AIR MIX DOOR MOTOR (DRIVER)" .
NG >> Repair or replace harness as necessary.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (PASSENGER)
1. CHECK RESULT FROM FRONT AIR CONTROL SELF-DIAGNOSIS
Self-diagnosis code 12 is present. Refer to ATC-53, "
A/C System Self-diagnosis Function" .
YES or NO
YES >> GO TO 2.
NO >> GO TO 3.
2. CHECK POWER SUPPLY CIRCUIT FOR AIR MIX DOOR MOTOR (PASSENGER)
1. Turn ignition switch OFF.
2. Disconnect front air control connector M50 and air mix door
motor (Passenger) connector M143.
3. Check continuity between front air control harness connector
M50 terminal 36 (G/W) and 37 (L) and air mix door motor (Pas-
senger) connector M143 terminal 1 (G/W) and 6 (L).
OK or NG
OK >> Replace air mix door motor (Passenger). Refer to AT C -
154, "FRONT AIR MIX DOOR MOTOR (PASSENGER)" .
NG >> Repair or replace harness as necessary.18 - Ground : Approx. 0V - 5V
LJIA0041E
4 - 18 Continuity should exist.
WJIA0590E
36 - 1 Continuity should exist.
37 - 6 Continuity should exist.
WJIA0548E

ATC-72
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
3. CHECK PBR REFERENCE SIGNAL VOLTAGE
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (Passenger) connector M143.
3. Turn ignition switch ON.
4. Check voltage between air mix door motor (Passenger) harness
connector M143 terminal 3 (Y) and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4. CHECK PBR REFERENCE VOLTAGE CIRCUIT BETWEEN AIR MIX DOOR (PASSENGER) AND
FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between air mix door motor (Passenger) har-
ness connector M143 terminal 3 (Y) and front air control harness
connector M49 terminal 2 (Y).
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
5. CHECK PBR GROUND REFERENCE CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between air mix door motor (Passenger) har-
ness connector M143 terminal 2 (P) and front air control harness
connector M49 terminal 15 (P).
OK or NG
OK >> GO TO 6.
NG >> Repair or replace harness as necessary.
6. CHECK PBR FEEDBACK SIGNAL
1. Reconnect front air control connector and air mix door motor
(Passenger) connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M50
terminal 41 (R/W) and ground.
4. Rotate temperature dial (Passenger) through complete range.
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL" .
NG >> GO TO 7. 3 - Ground : Approx.5V
LJIA0044E
3 - 2 Continuity should exist.
LJIA0045E
2 - 15 Continuity should exist.
WJIA0549E
41 - Ground : Approx. 0 - 5V
LJIA0047E

TROUBLE DIAGNOSIS
ATC-73
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
7. CHECK PBR FEEDBACK CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (Passenger) connector M143 and
front air control connector M50.
3. Check continuity between air mix door motor (Passenger) har-
ness connector M143 terminal 4 (R/W) and front air control har-
ness connector M50 terminal 41 (R/W).
OK or NG
OK >> Replace air mix door motor (Passenger). Refer to AT C -
154, "FRONT AIR MIX DOOR MOTOR (PASSENGER)"
.
NG >> Repair or replace harness as necessary.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (REAR)
1. CHECK RESULT FROM FRONT AIR CONTROL SELF-DIAGNOSIS
Self-diagnosis code 38 is present. Refer to ATC-53, "
A/C System Self-diagnosis Function" .
YES or NO
YES >> GO TO 2.
NO >> GO TO 3.
2. CHECK POWER SUPPLY CIRCUIT FOR AIR MIX DOOR MOTOR (REAR)
1. Turn ignition switch OFF.
2. Disconnect front air control connector M50 and air mix door
motor (Rear) connector B155.
3. Check continuity between front air control harness connector
M50 terminal 27 (GR/R) and air mix door motor (Rear) harness
connector B155 terminal 1 (GR/R) and between front air control
harness connector M50 terminal 28 (L/Y) and air mix door motor
(Rear) harness connector B155 terminal 6 (L/Y).
OK or NG
OK >> Replace air mix door motor (Rear). Refer to ATC-154, "REAR AIR MIX DOOR MOTOR" .
NG >> Repair or replace harness as necessary.
3. CHECK PBR REFERENCE SIGNAL VOLTAGE
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (Rear) connector B155.
3. Turn ignition switch ON.
4. Check voltage between air mix door motor (Rear) harness con-
nector B155 terminal 3 (Y) and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.4 - 41 : Continuity should exist.
WJIA0550E
27 - 1 Continuity should exist.
28 - 6 Continuity should exist.
LJIA0049E
3 - Ground : Approx. 5V
LJIA0050E

ATC-74
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
4. CHECK PBR REFERENCE VOLTAGE CIRCUIT BETWEEN AIR MIX DOOR MOTOR (REAR) AND
FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between air mix door motor (Rear) harness
connector B155 terminal 3 (Y) and front air control harness con-
nector M49 terminal 2 (Y).
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
5. CHECK PBR GROUND REFERENCE CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between air mix door motor (Rear) harness
connector B155 terminal 2 (P) and front air control harness con-
nector M49 terminal 15 (P).
OK or NG
OK >> GO TO 6.
NG >> Repair or replace harness as necessary.
6. CHECK PBR FEEDBACK SIGNAL
1. Reconnect front air control connector and air mix door motor
(Rear) connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M50
terminal 42 (R/Y) and ground.
4. Rotate rear temperature/mode dial (Front) through complete
range.
OK or NG
OK >> Replace front air control. Refer to ATC-135, "FRONT
AIR CONTROL" .
NG >> GO TO 7.3 - 2 Continuity should exist.
LJIA0051E
2 - 15 Continuity should exist.
LJIA0052E
42 - Ground : Approx. 0 - 5V
LJIA0053E

TROUBLE DIAGNOSIS
ATC-75
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
7. CHECK PBR FEEDBACK CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (Rear) connector B155 and front
air control connector M50.
3. Check continuity between air mix door motor (Rear) harness
connector B155 terminal 4 (R/Y) and front air control harness
connector M50 terminal 42 (R/Y).
OK or NG
OK >> Replace air mix door motor (Rear) ATC-154, "REAR AIR
MIX DOOR MOTOR" .
NG >> Repair or replace harness as necessary.4 - 42 Continuity should exist.LJIA0054E