2007 INFINITI QX56 service

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".
WJIA1791E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Water valve: F68 1 2 Rotate temperature
control dial Battery
voltage
WJIA1792E
1 - 29 : Continuity should exist.
1 - Ground : Continuity should not exist.
WJIA1793E

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
WJIA1794E
2 - 30 : Continuity should exist.
2 - Ground : Continuity should not exist.
WJIA1796E
WJIA0819E

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
WJIA0456E
1 - Ground : Approx. 5V
WJIA1273E
1 - 17 : Continuity should exist.
WJIA0564E

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.
WJIA0565E
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
WJIA1975E

TROUBLE DIAGNOSISATC-117
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The in-vehicle sensor is located on cluster lid D. It converts varia-
tions in temperature of passenger compartment air (drawn in through
the integrated fan) into a resistance value. It is then input into the
front air control.
DIAGNOSTIC PROCEDURE FOR IN-VEHICLE SENSOR
SYMPTOM: In-vehicle sensor circui t is open or shorted. Using the
CONSULT-II, DTC B2578 or B2579 is displayed. Without a CON-
SULT-II code 30, 31, 44 or 46 is indicated on front air control as a
result of conducting self-diagnosis.
1.CHECK IN-VEHICLE SENSOR CIRCUIT
Self-diagnosis DTC B2578 or B2579 (with CONSULT-II ) or code 30, 31 44 or 46 (without CONSULT-II) is
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 and ground.
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3.CHECK CIRCUIT CONTINUITY BET WEEN IN-VEHICLE SENSOR AND FRONT AIR CONTROL
WJIA0822E
WJIA0606E
WJIA0460E
4 - Ground : Approx. 5V.
LJIA0089E

ATC-118
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between in-vehicle sensor harness connectorM32 terminal 1 and front air control harness connector M49 ter-
minal 21.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4.CHECK IN-VEHICLE SENSOR
Refer to "In-vehicle 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 in-vehicle sensor. Refer to ATC-125
.
2. Go to ATC-48, "
A/C System Self-Diagnosis Function" and perform self-diagnosis.
5.CHECK CIRCUIT CONTINUITY BETWEEN IN- VEHICLE SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector.
3. Check continuity between in-vehicle sensor harness connector M32 terminal 4 and front air control harness connector M50 ter-
minal 32.
4. Check continuity between in-vehicle sensor harness connector M32 terminal 4 and ground.
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 >> Repair harness or connector.
6.CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHIC LE SENSOR MOTOR AND FRONT AIR CONTROL
(SELF-DIAGNOSIS CODES 30, 31, 44, 46 OR DTC B2578, B2579)
1. Turn ignition switch OFF.
2. Disconnect front air control connector and in-vehicle sensor con- nector.
3. Check continuity between in-vehicle sensor harness connector M32 terminal 2 and 3 and front air control harness connector
M50 terminal 44 and 43.
4. Check continuity between in-vehicle sensor harness connector M32 terminal 2 and 3 and ground.
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 >> Repair harness or connector. 1 - 21 : Continuity should exist.
LJIA0090E
4 - 32 : Continuity should exist.
4 - Ground Continuity should not exist.
LJIA0091E
2 - 44 : Continuity should exist.
3 - 43 : Continuity should exist.
2, 3 - Ground :Continuity should not exist.
LJIA0093E

TROUBLE DIAGNOSISATC-119
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COMPONENT INSPECTION
In-vehicle Sensor
After disconnecting in-vehicle sensor connector M32, measure resis-
tance between terminals 1 and 4 at sensor component side, using
the table below.
If NG, replace in-vehicle sensor.
Optical Sensor CircuitINFOID:0000000003533268
COMPONENT DESCRIPTION
The optical sensor is located in t he center of the defroster grille. It
detects sunload entering through windshield by means of a photo
diode. The sensor converts the sunload into a current value which is
then input into the front air control.
OPTICAL INPUT PROCESS
The front air control includes a processing circuit whic h averages the variations in detected sunload over a
period of time. This prevents adjustments in the ATC system operation due to small or quick variations in
detected sunload.
For example, consider driving along a road bordered by an occasional group of large trees. The sunload
detected by the optical sensor will vary whenever the tr ees obstruct the sunlight. The processing circuit aver-
ages the detected sunload over a period of time, so that the (insignificant) effect of the trees momentarily
obstructing the sunlight does not cause any change in t he ATC system operation. On the other hand, shortly
after entering a long tunnel, the system will recognize t he change in sunload, and the system will react accord-
ingly.
DIAGNOSTIC PROCEDURE FOR OPTICAL SENSOR
Temperature °C ( °F) Resistance k Ω
− 15 (5) 21.40
− 10 (14) 16.15
− 5 (23) 12.29
0 (32) 9.41
5 (41) 7.27
10 (50) 5.66
15 (59) 4.45
20 (68) 3.51
25 (77) 2.79
30 (86) 2.24
35 (95) 1.80
40 (104) 1.45 45 (113) 1.18
WJIA0825E
WJIA0569E