ignition INFINITI QX56 2007 Factory Service Manual

TROUBLE DIAGNOSISATC-95
< SERVICE INFORMATION >
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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 contro lled 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-85, "Rear Blower Motor Circuit" .
• Temperature and mode operation is malfunctioning.
1.CHECK OPERATION FROM FRONT AIR CONTROL
Does rear temperature and mode operat e normally from front air control?
YES or NO
YES >> GO TO 2.
NO >> Refer to ATC-59, "
Air Mix Door Motor Circuit".
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 AI R CONTROL AND AIR MIX DOOR MOTOR (REAR) FOR OPEN OR
SHORT
WJIA1132E
33 - 5 Continuity should exist.
5 - Ground Continuity should not exist.
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ATC-96
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
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. Refer to ATC-123, "Removal and Installation"
NG >> Repair harness or connector.
Magnet Clutch CircuitINFOID:0000000003533259
SYMPTOM: Magnet clutch does not engage.
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OP ERATIONAL CHECK - MAGNET CLUTCH
1. Turn ignition switch ON.
2. Press the A/C switch.
3. Press mode switch to select vent ( ) mode.
4. Display shows , A/C. Confirm that the compress or clutch engages (sound or visual inspection). (Dis-
charge air and blower speed will depend on ambi ent, in-vehicle and set temperatures.)
Can the symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to ATC-50, "
Operational Check (Front)" .
Does another symptom exist?
YES >> Refer to ATC-32, "How to Perform Trouble Diagnosis for Quick and Accurate Repair" .
NO >> System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis to check for any codes. Refer to ATC-48, "
A/C System Self-Diagnosis Function" .
Are any self-diagnosis codes present?
YES >> Refer to ATC-48, "A/C System Self-Diagnosis Function" .
NO >> GO TO 5.
5.CHECK AMBIENT SENSOR
Check and verify ambient sensor circuit. Refer to ATC-114, "
Ambient Sensor Circuit" .
>> GO TO 6.
6.CHECK INTAKE SENSOR
Check and verify intake sensor circuit. Refer to ATC-120, "
Intake Sensor Circuit" .
>> GO TO 7.
2 - 2 Continuity
should exist.
4 - 3 Continuity should exist.
2, 4 - Ground Continuity should not exist.
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ATC-98
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
YES or NO
YES >> • WITH CONSULT-IIGO 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 BETW EEN 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-28, "Removal and
Installation of IPDM E/R".
NG >> Replace magnet clutch. Refer to ATC-155, "
Removal
and Installation for Compressor Clutch".
5.CHECK BCM INPUT (COMPRESSOR ON) SIGNAL
Check compressor ON/OFF signal. Refer to ATC-30, "
CONSULT-II
Function (HVAC)" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.
6.CHECK CIRCUIT CONTINUITY BETWEE N 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.
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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27 - 12 Continuity should exist.
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TROUBLE DIAGNOSISATC-99
< SERVICE INFORMATION >
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7.CHECK VOLTAGE FOR FRONT AIR CO NTROL (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-123,
"Removal and Installation".
NG-2 >> If the voltage is approx. 0V when A/C switch is OFF, replace BCM. Refer to BCS-24, "
BCM".
8.CHECK REFRIGERANT PRESSURE SENSOR
WITH CONSULT-II
1. Start engine.
2. Check voltage of refrigerant pressure sensor. Refer to EC-638
.
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-638
.
9.CHECK BCM INPUT (FAN ON) SIGNAL
Check FAN ON/OFF signal. Refer to ATC-30, "
CONSULT-II Function
(HVAC)" .
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
10.CHECK CIRCUIT CONTINUITY BETWEE N BCM AND FRONT AIR CONTROL
Te r m i n a l s
Condition Voltage
(+)
(-)
Front air con-
trol connec- tor Te r m i n a l N o .
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
Condition Voltage
(+)
(-)
ECM con-
nector Te r m i n a l N o .
F54 70 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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ATC-100
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
1. Turn ignition switch OFF.
2. Disconnect BCM connector and front air control connector.
3. Check continuity between BCM harness connector M18 terminal28 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 moto r is ON, replace front air control. Refer to ATC-123,
"Removal and Installation" .
NG-2 >> If the voltage is approx. 0V when blower motor is OFF, replace BCM. Refer to BCS-24, "
BCM".
12.CHECK CAN COMMUNICATION
Check CAN communication. Refer to LAN-4
.
•BCM – ECM
• ECM – IPDM E/R
• ECM – Front air control
OK or NG
OK >> Inspection End.
NG >> Repair or replace malfunctioning part(s).
Insufficient CoolingINFOID:0000000003533260
SYMPTOM: Insufficient cooling
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPER ATIONAL CHECK - TEMPERATURE DECREASE
1. Press the AUTO switch.
2. Turn temperature control dial (driver) counterclockwise until 16 ° C (60 ° F) is displayed.
3. Check for cold air at discharge air outlets.
Can the symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to ATC-50, "
Operational Check (Front)" .
Does another symptom exist?
28 - 10 Continuity should exist.
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Te r m i n a l s
Condition Voltage
(+)
(-)
Front air con-
trol connector Te r m i n a l N o .
M49 10 Ground A/C switch: ON
Blower motor
operates
Approx. 0V
A/C switch: OFF Approx. 5V
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ATC-112
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
9.CHECK AIR MIX DOOR MOTORS PBR CIRCUIT
Check air mix door motors PBR circuit. Refer to ATC-59, "
Air Mix Door Motor Circuit" .
OK or NG
OK >> GO TO 10.
NG >> Repair or replace as necessary.
10.RECHECK FOR SYMPTOMS
Perform a complete operational check for any symptoms. Refer to ATC-50, "
Operational Check (Front)" .
Does another symptom exist?
YES >> Refer to ATC-32, "How to Perform Trouble Diagnosis for Quick and Accurate Repair" .
NO >> Replace front air control. Refer to ATC-123, "
Removal and Installation".
Memory FunctionINFOID:0000000003533264
SYMPTOM: Memory function does not operate.
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OP ERATIONAL CHECK - MEMORY FUNCTION
1. Set the temperature to 32 °C (90 °F).
2. Rotate the front blower control dial (driver) to turn system OFF.
3. Turn ignition switch OFF.
4. Turn ignition switch ON.
5. Press the AUTO switch.
6. Confirm that the set temperature remains at previous temperature.
7. Rotate the front blower control dial (driver) to turn system OFF.
Can the symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.PERFORM COMPLETE OPERATIONAL CHECK
Perform a complete operational check and check for any symptoms. Refer to ATC-50, "
Operational Check
(Front)" .
Can a symptom be duplicated?
YES >> Refer to ATC-32, "How to Perform Trouble Diagnosis for Quick and Accurate Repair".
NO >> System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis to check for any codes. Refer to ATC-48, "
A/C System Self-Diagnosis Function".
Are any self-diagnosis codes present?
YES >> Refer to ATC-48, "A/C System Self-Diagnosis Function" .
NO >> GO TO 5.
5.CHECK POWER AND GROUND CIRCUIT
Check main power supply and ground circuit. Refer to ATC-52, "
Power Supply and Ground Circuit for Front Air
Control".
OK or NG
OK >> GO TO 6.
NG >> Repair or replace as necessary.
6.RECHECK FOR SYMPTOMS
Perform a complete operational check for any symptoms. Refer to ATC-50, "
Operational Check (Front)".

TROUBLE DIAGNOSISATC-113
< SERVICE INFORMATION >
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Does another symptom exist?
YES >> Refer to ATC-32, "How to Perform Trouble Diagnosis for Quick and Accurate Repair".
NO >> Replace front air control. Refer to ATC-123, "
Removal and Installation".
Water Valve CircuitINFOID:0000000003533265
COMPONENT DESCRIPTION
Water Valve
The water valve (1) cuts the flow of engine coolant to the front and
rear heater cores to allow for maximum cooling during A/C opera-
tion. It is controlled by the front air control.
DIAGNOSTIC PROCEDURE FOR WATER VALVE
1.CHECK WATER VALVE POWER AND GROUND CIRCUITS
1. Disconnect water valve connector F68.
2. Turn ignition switch ON.
3. Rotate temperature control dial (driver) to 32 °C (90 °F).
4. Check voltage between water valve harness connector F68 ter- minal 1 and terminal 2 while rotating temperature control dial
(driver) to 16 °C (60 °F).
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2.CHECK WATER VALVE CONTROL OUTPUT CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front air control connector M50.
3. Check continuity between water valve harness connector F68 (A) terminal 1 and front air control harness connector M50 (B)
terminal 29.
4. Check continuity between water valve harness connector F68 (A) terminal 1 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-123, "Removal and Installation".
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ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Water valve: F68 1 2 Rotate temperature
control dial Battery
voltage
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1 - 29 : Continuity should exist.
1 - Ground : Continuity should not exist.
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ATC-114
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
NG >> Repair harness or connector.
3.CHECK WATER VALVE POWER AND GROUND CIRCUITS
1. Rotate temperature control dial (driver) to 16 °C (60 °F).
2. Check voltage between water valve harness connector F68 ter- minal 1 and terminal 2 while rotating temperature control dial
(driver) to 32 °C (90 °F).
OK or NG
OK >> Replace the water valve.
NG >> GO TO 4.
4.CHECK WATER VALVE CONTROL OUTPUT CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front air control connector M50.
3. Check continuity between water valve harness connector F68 (A) terminal 2 and front air control harness connector M50 (B)
terminal 30.
4. Check continuity between water valve harness connector F68 (A) terminal 2 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-123, "Removal and Installation" .
NG >> Repair harness or connector.
Ambient Sensor CircuitINFOID:0000000003533266
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, t he 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 co mpartment can radiate to the front grille area, loca-
tion of the ambient sensor.
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Water valve: F68 2 1 Rotate temperature
control dial Battery
voltage
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2 - 30 : Continuity should exist.
2 - Ground : Continuity should not exist.
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TROUBLE DIAGNOSISATC-115
< SERVICE INFORMATION >
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DIAGNOSTIC PROCEDURE FOR AMBIENT SENSOR
SYMPTOM: Ambient sensor circui t 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 and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
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 am bient sensor harness connector
E1 terminal 1 and front air control harness connector M49 termi-
nal 17.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3.CHECK AMBIENT SENSOR
Refer to "Ambient Sensor Circuit" .
OK or NG
OK >> 1. Replace front air control. Refer to ATC-123, "Removal and Installation"
2. Go to ATC-48, "A/C System Self-Diagnosis Function" and perform self-diagnosis.
NG >> 1. Replace ambient sensor. Refer to ATC-124
.
2. Go to ATC-48, "
A/C System Self-Diagnosis Function" and perform self-diagnosis.
4.CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND FRONT AIR CONTROL
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1 - Ground : Approx. 5V
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1 - 17 : Continuity should exist.
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ATC-116
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
1. Turn ignition switch OFF.
2. Disconnect front air control connector.
3. Check continuity between ambient sensor harness connector
E1 terminal 2 and front air control harness connector M49 termi-
nal 21.
4. Check continuity between am bient sensor harness connector
E1 terminal 2 and ground.
OK or NG
OK >> 1. Replace front air control. Refer to ATC-123, "Removal and Installation"
2. Go to self-diagnosis ATC-48, "A/C System Self-Diagnosis Function" and perform self-diagno-
sis.
NG >> Repair harness or connector.
COMPONENT INSPECTION
Ambient Sensor
After disconnecting ambient sensor (1) connector E1, measure
resistance between terminals 1 and 2 at sensor component side,
using the table below.
If NG, replace ambient sensor.
In-vehicle Sensor CircuitINFOID:0000000003533267
COMPONENT DESCRIPTION
In-vehicle Sensor
2 - 21 : Continuity should exist.
2 - Ground : Continuity should not exist.
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Temperature °C ( °F) Resistance k Ω
− 15 (5) 12.73
− 10 (14) 9.92
− 5 (23) 7.80
0 (32) 6.19
5 (41) 4.95
10 (50) 3.99
15 (59) 3.24
20 (68) 2.65
25 (77) 2.19
30 (86) 1.81
35 (95) 1.51
40 (104) 1.27 45 (113) 1.07
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