ignition INFINITI QX4 2005 Factory Service Manual

ATC-114
TROUBLE DIAGNOSIS
Revision: October 20052005 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 (V) and rear air control harness connector
R209 terminal 5 (V).
4. Check continuity between rear air control harness connector
R209 terminal 5 (V) 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 (P) and 4 (Y) and air mix door motor (rear) har-
ness connector B155 terminal 2 (P) and 3 (Y).
3. Check continuity between rear air control harness connector
R209 terminals 2 (P) and 4 (Y) 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 - 2 Continuity should exist.
4 - 3 Continuity should exist.
2, 4 - Ground Continuity should not exist.
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TROUBLE DIAGNOSIS
ATC-117
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Revision: October 20052005 QX56
2. PERFORM AUTO ACTIVE TEST
Refer to PG-22, "
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 (Y/B) and compressor harness connector F3 termi-
nal 1 (Y/B).
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-28, "Removal and
Installation of IPDM E/R" .
NG >> Replace magnet clutch. Refer to ATC-180, "
Removal
and Installation for Compressor Clutch" .
5. CHECK BCM INPUT (COMPRESSOR ON) SIGNAL
Check compressor ON/OFF signal. Refer to ATC-33, "
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: October 20052005 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 (W/R) and front air control harness connector M49 terminal
12 (W/R).
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 (W/R) 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-147,
"FRONT AIR CONTROL" .
NG-2 >> If the voltage is approx. 0V when A/C switch is OFF, replace BCM. Refer to BCS-20, "
Removal
and Installation of BCM" . 27 - 12 Continuity should exist.
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Terminals
Condition Voltage (+)
(-) Front air
control con-
nectorTe r m i n a l N o .
(Wire color)
M49 12 (W/R) GroundA/C switch: ON Approx. 0V
A/C switch: OFF Approx. 5V
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TROUBLE DIAGNOSIS
ATC-119
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8. CHECK REFRIGERANT PRESSURE SENSOR
WITH CONSULT-II
1. Start engine.
2. Check voltage of refrigerant pressure sensor. Refer to ATC-33, "
CONSULT-II Function (HVAC)" .
WITHOUT CONSULT-II
1. Start engine.
2. Check voltage between ECM harness connector F54 terminal
70 (B/W) and ground.
OK or NG
OK >>
WITH CONSULT-II
GO TO 9.

WITHOUT CONSULT-II
GO TO 10.
NG >> Refer to EC-643, "
REFRIGERANT PRESSURE SENSOR" .
9. CHECK BCM INPUT (FAN ON) SIGNAL
Check FAN ON/OFF signal. Refer to ATC-33, "
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 (L/R) and front air control harness connector M49 terminal 10
(L/R).
OK or NG
OK >> GO TO 11.
NG >> Repair harness or connector.
Te r m i n a l s
Condition Voltage (+)
(-)
ECM con-
nectorTe r m i n a l N o .
(Wire color)
F54 70 (B/W) Ground A/C switch: ON Approx. 0.36 - 3.88V
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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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ATC-120
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
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 (L/R) 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-147,
"FRONT AIR CONTROL" .
NG-2 >> If the voltage is approx. 0V when blower motor is OFF, replace BCM. Refer to BCS-20, "
Removal
and Installation of BCM" .
12. CHECK CAN COMMUNICATION
Check CAN communication. Refer to LAN-5, "
CAN COMMUNICATION" .

BCM – ECM

ECM – IPDM E/R

ECM – Front air control
OK or NG
OK >> Inspection End.
NG >> Repair or replace malfunctioning part(s).
Terminals
Condition Voltage (+)
(-)
Front air con-
trol connectorTe r m i n a l N o .
(Wire color)
M49 10 (L/R) GroundA/C switch: ON
Blower motor
operatesApprox. 0V
A/C switch: OFF Approx. 5V
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ATC-134
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
DIAGNOSTIC PROCEDURE FOR WATER VALVE
1. CHECK WATER VALVE RELAY POWER INPUT CIRCUITS
1. Turn ignition switch OFF.
2. Disconnect water valve relay connector M7.
3. Check voltage between water valve relay harness connector ter-
minals and ground.
OK or NG
OK >> GO TO 2.
NG >> Repair harness or connector.
2. CHECK WATER VALVE CONTROL
1. Turn ignition switch ON.
2. Select MAX A/C with mode switch.
3. Check continuity between water valve relay harness connector
M7 terminal 1 (W/G) and ground, as MAX A/C is switched OFF
and ON.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. CHECK WATER VALVE CONTROL OUTPUT CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front air control connector M50.
3. Check continuity between water valve relay harness connector
M7 terminal 1 (W/G) and front air control harness connector
M50 terminal 29 (W/G).
4. Check continuity between water valve relay harness connector
M7 terminal 1 (W/G) 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 ON Water valve
relay con-
nectorTe r m i n a l N o .
(Wire color)
M72 (Y/R)
GroundBattery voltage Battery voltage
3 (Y/G) 0V Battery voltage
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Terminals
Condition Continuity (+)
(-) Water valve
relay con-
nectorTe r m i n a l N o .
(Wire color)
M7 1 (W/G) GroundMAX A/C: ON Yes
MAX A/C: OFF No
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1 - 29 : Continuity should exist.
1 - Ground : Continuity should not exist.
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TROUBLE DIAGNOSIS
ATC-135
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Revision: October 20052005 QX56
4. CHECK WATER VALVE RELAY
Check water valve relay. Refer to ATC-136, "
Wat er Va lve Relay" .
OK or NG
OK >> GO TO 5
NG >> Replace water valve relay.
5. CHECK WATER VALVE GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect water valve connector F68.
3. Check continuity between water valve harness connector F68
terminal - (B) and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.
6. CHECK WATER VALVE POWER CIRCUIT
1. Check continuity between water valve relay connector terminal 5
(Y/L) and water valve connector F68 terminal + (Y/L)
2. Check continuity between water valve relay harness connector
M7 terminal 5 (Y/L) and ground.
OK or NG
OK >> Replace water valve.
NG >> Repair harness or connector.(-) - Ground : Continuity should exist.
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5 - + : Continuity should exist.
5 - Ground : Continuity should not exist.
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TROUBLE DIAGNOSIS
ATC-137
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Revision: October 20052005 QX56
Ambient Sensor CircuitEJS003Y2
COMPONENT DESCRIPTION
Ambient Sensor
The ambient sensor is attached on the radiator core support (left
side). It detects ambient temperature and converts it into a value
which is then input into the front air control.
AMBIENT TEMPERATURE INPUT PROCESS
The front air control includes a processing circuit for the ambient sensor input. However, when the tempera-
ture detected by the ambient sensor increases quickly, the processing circuit retards the front air control func-
tion. It only allows the front air control to recognize an ambient temperature increase of 0.33°C (0.6°F) per 100
seconds.
This prevents constant adjustments due to momentary conditions, such as stopping after high speed driving.
Although the actual ambient temperature has not changed, the temperature detected by the ambient sensor
will increase. This is because the heat from the engine compartment can radiate to the front grille area, loca-
tion of the ambient sensor.
DIAGNOSTIC PROCEDURE FOR AMBIENT SENSOR
SYMPTOM: Ambient sensor circuit is open or shorted. Using the
CONSULT-II, DTC B257B or B257C is displayed. Without a CON-
SULT-II, code 40 or 41 is indicated on front air control as a result of
conducting the front air control self-diagnosis.
1. CHECK VOLTAGE BETWEEN AMBIENT SENSOR AND GROUND
1. Disconnect ambient sensor connector.
2. Turn ignition switch ON.
3. Check voltage between ambient sensor harness connector E1
terminal 1 (P) and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
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1 - Ground : Approx. 5V
WJIA1971E

ATC-138
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
2. CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector.
3. Check continuity between ambient sensor harness connector
E1 terminal 1 (P) and front air control harness connector M49
terminal 17 (P).
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3. CHECK AMBIENT SENSOR
Refer to ATC-137, "
Ambient Sensor Circuit" .
OK or NG
OK >> 1. Replace front air control. Refer to ATC-147, "FRONT AIR CONTROL"
2. Go to self-diagnosis AT C - 5 5 , "A/C System Self-diagnosis Function" and perform self-diagno-
sis.
NG >> 1. Replace ambient sensor.
2. Go to self-diagnosis AT C - 5 5 , "
A/C System Self-diagnosis Function" and perform self-diagno-
sis.
4. CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector.
3. Check continuity between ambient sensor harness connector
E1 terminal 2 (V/R) and front air control harness connector M49
terminal 21 (V/R).
4. Check continuity between ambient sensor harness connector
E1 terminal 2 (V/R) and ground.
OK or NG
OK >> 1. Replace front air control. Refer to ATC-147, "FRONT AIR CONTROL"
2. Go to self-diagnosis AT C - 5 5 , "A/C System Self-diagnosis Function" and perform self-diagno-
sis.
NG >> Repair harness or connector.1 - 17 : Continuity should exist.
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2 - 21 : Continuity should exist.
2 - Ground : Continuity should not exist.
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TROUBLE DIAGNOSIS
ATC-141
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Revision: October 20052005 QX56
DIAGNOSTIC PROCEDURE FOR IN-VEHICLE SENSOR
SYMPTOM: in-vehicle sensor circuit is open or shorted. Using the
CONSULT-II, DTC B2578 or B2579 is displayed. Without a CON-
SULT-II, code 30 or 31 is indicated on front air control as a result of
conducting the front air control self-diagnosis.
1. CHECK IN-VEHICLE SENSOR CIRCUIT
Are diagnostic codes 30, 31 or DTC B2578, B2579 present?
YES or NO
YES >> GO TO 6.
NO >> GO TO 2.
2. CHECK VOLTAGE BETWEEN IN-VEHICLE SENSOR AND GROUND
1. Disconnect in-vehicle sensor connector.
2. Turn ignition switch ON.
3. Check voltage between in-vehicle sensor harness connector
M32 terminal 4 (LG/R) and ground.
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between in-vehicle sensor harness connector
M32 terminal 1 (V/R) and front air control harness connector
M49 terminal 21 (V/R).
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK IN-VEHICLE SENSOR
Refer to ATC-145, "
Intake Sensor Circuit" .
OK or NG
OK >> 1. Replace front air control. Refer to ATC-147, "FRONT AIR CONTROL" .
2. Go to AT C - 5 5 , "
A/C System Self-diagnosis Function" and perform self-diagnosis.
NG >> 1. Replace in-vehicle sensor. Refer to ATC-149, "
IN-VEHICLE SENSOR" .
2. Go to AT C - 5 5 , "
A/C System Self-diagnosis Function" and perform self-diagnosis.
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4 - Ground : Approx. 5V.
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1 - 21 : Continuity should exist.
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