2007 INFINITI QX56 engine

TROUBLE DIAGNOSISATC-109
< SERVICE INFORMATION >
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OK >> GO TO 6.
NG >> Check the air mix door motor circuit. Refer to ATC-59, "
Air Mix Door Motor Circuit" .
6.CHECK AIR DUCTS
Check for disconnected or leaking air ducts.
OK or NG
OK >> GO TO 7.
NG >> Repair all disconnected or leaking air ducts.
7.CHECK HEATER HOSE TEMPERATURES
1. Start engine and warm it up to normal operating temperature.
2. Touch both the inlet and outlet heater hoses.
OK or NG
OK >> Hot inlet hose and a warm outlet hose: GO TO 8.
NG >> • Inlet hose cold: GO TO 11. • Both hoses warm: GO TO 9.
8.CHECK ENGINE COOLANT SYSTEM
Check engine control temperature sensor. Refer to EC-205
.
OK or NG
OK >> System OK.
NG >> Repair or replace as necessary. Retest.
9.CHECK HEATER HOSES
Check heater hoses for proper installation.
OK or NG
OK >> System OK.
NG >> 1. Back flush heater core. 2. Drain the water from the system.
3. Refill system with new engine coolant. Refer to CO-9, "
Changing Engine Coolant" .
4. GO TO 10 to retest.
10.CHECK HEATER HOSE TEMPERATURES
1. Start engine and warm it up to normal operating temperature.
2. Touch both the inlet and outlet heater hoses.
OK or NG
OK >> System OK.
NG >> Replace heater core. Refer to ATC-135
.
11 .CHECK WATER VALVE
Check the operation of the water valve. Refer to ATC-113, "
Water Valve Circuit".
OK or NG
OK >> System OK.
NG >> Replace water valve.
NoiseINFOID:0000000003533262
SYMPTOM: Noise
INSPECTION FLOW

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

HEATER & COOLING UNIT ASSEMBLYATC-133
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Rear Heater and Cooling Unit Assembly
Removal and InstallationINFOID:0000000003533279
FRONT HEATER AND COOLING UNIT ASSEMBLY
Removal
1. Move the two front seats to the rearmost position on the seat track.
2. Disconnect the battery negative terminal and battery positive terminal.
3. Discharge the refrigerant from the A/C system. Refer to ATC-150, "
HFC-134a (R-134a) Service Proce-
dure".
4. Drain the coolant from the engine cooling system. Refer to MA-12, "
Changing Engine Coolant".
WJIA2315E
1. Rear heater and cooling unit assembly 2. Rear A/C pipes 3. Rear A/C heater core pipes
4. Rear heater core hose 5. Rear blower motor 6. Underfloor rear A/C pipes
7. Underfloor rear heater core pipes A. Bolt torque specifications B. Leak checking order (l - r)
C. Tightening torque D. Wrench size E. O-ring size
⇐Front
NOTE: The O-ring size 8 is the high-side and the O-ring size 16 is the low-side.

ATC-134
< SERVICE INFORMATION >
HEATER & COOLING UNIT ASSEMBLY
5. Disconnect the front heater hoses from the front heater core.
6. Disconnect the high/low pressure pipes from the front expansion valve.
7. Remove the instrument panel and console panel. Refer to IP-10, "
Removal and Installation".
8. Remove the steering column. Refer to PS-10
.
9. Disconnect the instrument panel wire harness at the RH and LH in-line connector brackets, and the fuse
block (J/B) electrical connectors. Refer to PG-3
.
10. Disconnect the steering member from each side of the vehicle body.
11. Remove the front heater and cooling unit assembly with it attached to the steering member, from the vehi-
cle.
CAUTION:
Use care not to damage the seats and interior tr im panels when removing the front heater and
cooling unit assembly with it at tached to the steering member.
12. Remove the front heater and cooling unit assembly from the steering member.
Installation
Installation is in the reverse order of removal.
CAUTION:
• Replace the O-ring of the low-pressure pipe and high-pressure pipe with a new one, and apply com-
pressor oil to it when installing it.
• After charging the refrigerant, check for leaks.
NOTE:
• Fill the engine cooling system with the s pecified coolant mixture. Refer to MA-12, "
Changing Engine Cool-
ant".
• Recharge the A/C system. Refer to ATC-150, "
HFC-134a (R-134a) Service Procedure".
REAR HEATER AND COOLING UNIT ASSEMBLY
Removal
1. Discharge the refrigerant from the A/C system. Refer to ATC-150, "HFC-134a (R-134a) Service Proce-
dure".
2. Drain the coolant from the engine cooling system. Refer to MA-12, "
Changing Engine Coolant".
3. Disconnect the rear heater core hoses from the rear heater core.
4. Disconnect the rear A/C pipes from the rear expansion valve.
5. Remove the luggage side finisher lower RH. Refer to EI-34
.
6. Disconnect the following electrical connectors: • Rear blower motor
• Rear blower motor resistor
• Rear air mix door motor
7. Disconnect the ducts from the rear heater and cooling unit assembly.
8. Remove the rear heater and cooling unit assembly.
Installation
Installation is in the reverse order of removal.
CAUTION:
• Replace the O-ring of the low-pressure pipe and high-pressure pipe with a new one, and apply com-
pressor oil to it when installing it.
• After charging the refrigerant, check for leaks.
NOTE:
• Fill the engine cooling system with the s pecified coolant mixture. Refer to MA-12, "
Changing Engine Cool-
ant".
• Recharge the A/C system. Refer to ATC-150, "
HFC-134a (R-134a) Service Procedure".
LJIA0021E

HEATER COREATC-137
< SERVICE INFORMATION >
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5. Remove the heater core. NOTE:
If the in-cabin microfilters are c ontaminated from coolant leaking
from the heater core, replace the in-cabin microfilters with new
ones before installing the new heater core.
Installation
Installation is in the reverse order of removal.
REAR HEATER CORE
Removal
1. Partially drain the engine cooling system. Refer to MA-12, "Changing Engine Coolant".
2. Remove the luggage side finisher lower RH. Refer to EI-39
.
3. Disconnect the rear heater hoses from the heater core.
4. Remove the rear heater core bracket.
5. Remove the heater core.
Installation
Installation is in the reverse order of removal.
LJIA0134E
LJIA0069E
LJIA0071E

ATC-154
< SERVICE INFORMATION >
REFRIGERANT LINES
Removal and Installation for Compressor
INFOID:0000000003533293
A/C Compressor Mounting
REMOVAL
1. Discharge the refrigerant. Refer to ATC-150, "HFC-134a (R-134a) Service Procedure".
2. Remove the front right wheel and tire assembly. Refer to WT-7, "
Rotation".
3. Remove the engine under cover and the splash shield using power tool.
4. Remove the engine air cleaner and air ducts. Refer to EM-15
.
5. Remove the drive belt. Refer to EM-13
.
6. Disconnect the compressor electrical connector.
7. Disconnect the high-pressure flexible hose and low- pressure flexible hose from the compressor.
CAUTION:
Cap or wrap the joint of the pipe with suitable mate rial such as vinyl tape to avoid the entry of air.
8. Remove the compressor bolts and nut using power tools.
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:
• Replace the O-rings of the low-pressure flexibl e hose and high-pressure flexible hose with new
ones, apply compressor oil to the O-rings when installing them.
• After recharging the A/C system with refrigerant, check for leaks.
WJIA0958E

REFRIGERANT LINESATC-157
< SERVICE INFORMATION >
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3. Install the pulley assembly using Tool and a wrench, then install the snap ring using snap ring pliers.
4. Install the clutch disc on the co mpressor shaft, together with the
original shim(s). Press the clutch disc down by hand.
5. Install the clutch pulley bolt using Tool, to prevent the clutch disc from turning and tighten the bolt to specification.
CAUTION:
After tightening the clutch pul ley bolt, check that the clutch
pulley rotates smoothly.
6. Check the pulley clearance all the way around the clutch disc as shown.
7. If the specified clearance is not obtained, replace the adjusting spacer to readjust.
8. Connect the compressor electrical connector.
9. Install the drive belt. Refer to EM-13
.
10. Install the engine under cover and the splash shield. Tool number : — (J-38873-A)
WJIA1016E
WHA184
Tool number : J-44614
WHA229
Clutch disc-to-pulley clearance : 0.3 - 0.6 mm
(0.012 - 0.024 in)
WHA194