ignition INFINITI QX4 2005 Factory Service Manual

TROUBLE DIAGNOSIS
ATC-63
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Revision: October 20052005 QX56
1. CHECK POWER SUPPLY CIRCUITS FOR FRONT AIR CONTROL
1. Disconnect front air control connector.
2. Check voltage between front air control harness connector M49
terminals 14 (Y/G) and 22 (Y/R), and ground.
OK or NG
OK >> GO TO 2.
NG >> Check 10A fuses [Nos. 8 and 19, located in the fuse block (J/B)]. Refer to PG-76, "
FUSE BLOCK-
JUNCTION BOX(J/B)" .

If fuses are OK, check harness for open circuit. Repair or replace as necessary.

If fuses are NG, replace fuse and check harness for short circuit. Repair or replace as neces-
sary.
2. CHECK GROUND CIRCUIT FOR FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Check continuity between front air control harness connector
M49 terminal 1 (B) and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-147, "FRONT
AIR CONTROL" .
NG >> Repair harness or connector.
Terminals Ignition switch position
(+)
(-) OFF ACC ON Front air
control
connectorTe r m i n a l N o .
(Wire color)
M49 14 (Y/G)
GroundApprox. 0V Approx. 0VBattery
voltage
M49 22 (Y/R)Battery
voltageBattery
voltageBattery
voltage
WJIA0415E
1 - Ground : Continuity should exist.
WJIA1351E

ATC-66
TROUBLE DIAGNOSIS
Revision: October 20052005 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-147, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
WJIA0587E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M496 5Press
mode
switchBattery
voltage
WJIA1727E
5 - Ground : Continuity should not exist.
6 - Ground : Continuity should not exist.
WJIA1734E

TROUBLE DIAGNOSIS
ATC-67
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Revision: October 20052005 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-147, "
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-165, "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.
ConnectorTerminals
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M495 6Press
mode
switchBattery
voltage
WJIA1742E
Continuity should exist.
WJIA1728E
5 - 5 : Continuity should exist.
6 - 6 : Continuity should exist.
LJIA0027E
ConnectorTe r m i n a l s
Voltage
(Approx.)
(+) (-)
Front air control: M49 2 15 5V
WJIA1729E

ATC-68
TROUBLE DIAGNOSIS
Revision: October 20052005 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-147, "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
(B) M142 terminal 3, 1 and front air control harness connector
(A) M49 terminal 2, 15.
OK or NG
OK >> Replace mode door motor. Refer to ATC-165, "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

TROUBLE DIAGNOSIS
ATC-69
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Revision: October 20052005 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-147, "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-165, "Removal
and Installation" .
NG >> Repair or replace harness as necessary.Continuity should not exist.
WJIA1733E
Continuity should exist.
LJIA0034E

ATC-72
TROUBLE DIAGNOSIS
Revision: October 20052005 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 FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32°C (90°F).
3. Check voltage between front air control harness connector M49
terminal 3 and terminal 4 while rotating temperature control dial
(driver) to 16°C (60°F).
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
WJIA1876E
WJIA1877E
WJIA1245E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M493 4Rotate temp
control dialBattery
voltage
WJIA1735E

TROUBLE DIAGNOSIS
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Revision: October 20052005 QX56
2. CHECK AIR MIX DOOR MOTOR (DRIVER) 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 3, 4 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-147, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
3. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32°C (90°F).
3. Check voltage between front air control harness connector M49
terminal 3 and terminal 4 while rotating temperature control dial
(driver) to 16°C (60°F).
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-147, "
FRONT AIR CONTROL" .
4. CHECK AIR MIX DOOR MOTOR (DRIVER) 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 3 and terminal 4.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR OPEN
1. Disconnect the air mix door motor (driver) harness connector.
2. Check continuity between front air control harness connector
M49 terminal 3, 4 and the air mix door motor (driver) harness
connector M147 terminal 1, 6.
OK or NG
OK >> Replace air mix door motor (driver). Refer to ATC-166,
"FRONT AIR MIX DOOR MOTOR (DRIVER)" .
NG >> Repair or replace harness as necessary.3 - Ground : Continuity should not exist.
4 - Ground : Continuity should not exist.
WJIA1736E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M494 3Rotate temp
control dialBattery
voltage
WJIA1737E
Continuity should exist.
WJIA1738E
3 - 1 : Continuity should exist.
4 - 6 : Continuity should exist.
WJIA0588E

ATC-74
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
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.
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-147, "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 air mix door motor (driver) harness connector.
2. Check continuity between air mix door motor (driver) harness
connector M147 (B) terminal 3, 2 and front air control harness
connector M49 (A) terminal 2, 15.
OK or NG
OK >> Replace air mix door motor (driver). Refer to ATC-166,
"FRONT AIR MIX DOOR MOTOR (DRIVER)" .
NG >> Repair or replace harness as necessary.
ConnectorTe r m i n a l s
Voltage
(Approx.)
(+) (-)
Front air control: M49 2 15 5V
WJIA1729E
Continuity should not exist.
WJIA1730E
Continuity should exist.
WJIA1731E
2 - 3 : Continuity should exist.
15 - 2 : Continuity should exist.
WJIA1777E

TROUBLE DIAGNOSIS
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Revision: October 20052005 QX56
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 18 and ground while rotating temperature control dial
from 32°C (90°F) to 16°C (60°F).
OK or NG
OK >> GO TO 12.
NG >> GO TO 11.
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 18 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-147, "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 air mix door motor (driver) harness connector
and front air control harness connector.
3. Check continuity between air mix door motor (driver) harness
connector M147 terminal 4 and front air control harness connec-
tor M49 terminal 18.
OK or NG
OK >> Replace air mix door motor (driver). Refer to ATC-166,
"FRONT AIR MIX DOOR MOTOR (DRIVER)" .
NG >> Repair or replace harness as necessary. Voltage : Approx. .5V - 4.5V
LJIA0041E
Continuity should not exist.
WJIA1739E
Continuity should exist.
WJIA0590E

ATC-76
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (PASSENGER)
1. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (passenger) to 32°C (90°F).
3. Check voltage between front air control harness connector M50
terminal 36 and terminal 37 while rotating temperature control
dial (passenger) to 16°C (60°F).
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. CHECK AIR MIX DOOR MOTOR (PASSENGER) 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
M50 terminal 36, 37 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-147, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
3. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (passenger) to 16°C (60°F).
3. Check voltage between front air control harness connector M50
terminal 36 and terminal 37 while rotating temperature control
dial (passenger) to 32°C (90°F).
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-147, "
FRONT AIR CONTROL" .
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M5037 36Rotate temp
control dialBattery
voltage
WJIA1740E
36 - Ground : Continuity should not exist.
37 - Ground : Continuity should not exist.
WJIA1741E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M5036 37Rotate temp
control dialBattery
voltage
WJIA1778E