service INFINITI QX56 2007 Factory Service Manual

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.
WJIA0450E
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
WJIA0451E

TROUBLE DIAGNOSISATC-101
< SERVICE INFORMATION >
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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 3.
4.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis Refer to ATC-48, "
A/C System Self-Diagnosis Function" .
OK or NG
OK >> GO TO 5.
NG >> Refer to ATC-48, "
A/C System Self-Diagnosis Function" .
5.CHECK DRIVE BELTS
Check compressor belt tension. Refer to EM-13, "
Checking Drive Belts" .
OK or NG
OK >> GO TO 6.
NG >> Adjust or replace compressor belt. Refer to EM-13, "
Removal and Installation" .
6.CHECK AIR MIX DOOR OPERATION
Check and verify air mix door me chanism for smooth operation.
Does air mix door operate correctly?
YES >> GO TO 7.
NO >> Repair or replace air mix door control linkage.
7.CHECK COOLING FAN MOTOR OPERATION
Check and verify cooling fan moto r for smooth operation. Refer to EC-469, "
Description" .
Does cooling fan motor operate correctly?
YES >> GO TO 8.
NO >> Check cooling fan motor. Refer to EC-469
.
8.CHECK WATER VALVE OPERATION
Check and verify water valve for smooth operation. Refer to ATC-113, "
Water Valve Circuit".
Does water valve operate correctly?
YES >> GO TO 8.
NO >> Check water valve circuit. Refer to ATC-113, "
Water Valve Circuit" .
9.CHECK RECOVERY/RECYCLING EQUIPMENT BEFORE USAGE
Check recovery/recycling equipment befor e connecting to vehicle. Verify there is no pressure in the recovery/
recycling equipment by checking the gauges. If pressure exists, recover refrigerant from equipment lines.
>> GO TO 9.
10.CHECK REFRIGERANT PURITY
1. Connect recovery/recycling equipment to vehicle.
2. Confirm refrigerant purity in supply tank us ing recovery/recycling and refrigerant identifier.
OK or NG
OK >> GO TO 10.
NG >> Check contaminated refrigerant. Refer to AT C - 3 , "
Contaminated Refrigerant" .
11 .CHECK FOR EVAPORATOR FREEZE UP
Start engine and run A/C. Check for evaporator freeze up.
Does evaporator freeze up?
YES >> Perform performance test diagnoses. Refer to "PERFORMANCE TEST DIAGNOSES" .
NO >> GO TO 11.

ATC-102
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
12.CHECK REFRIGERANT PRESSURE
Check refrigerant pressure with manifold gauge connected. Refer to "Test Reading" .
OK or NG
OK >> Perform performance test diagnoses. Refer to "PERFORMANCE TEST DIAGNOSES" .
NG >> GO TO 12.
13.CHECK AIR DUCTS
Check ducts for air leaks.
OK or NG
OK >> System OK.
NG >> Repair air leaks.
PERFORMANCE TEST DIAGNOSES

TROUBLE DIAGNOSISATC-103
< SERVICE INFORMATION >
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*1 "PERFORMANCE CHART" *2 "PERFORMANCE CHA RT" *3 "Trouble Diagnoses for Unusual
Pressure"
*4 AT C - 5 9 , "
Air Mix Door Motor Circuit"
RJIA1601E

ATC-104
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
PERFORMANCE CHART
Test Condition
Testing must be performed as follows:
*1ATC-155, "Removal and Installation
for Compressor Clutch"
*2AT C - 7 8 , "Front Blower Motor Circuit"*3EM-13, "Checking Drive Belts"
WJIA1371E

TROUBLE DIAGNOSISATC-105
< SERVICE INFORMATION >
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Test Reading
Recirculating-to-discharge Air Temperature Table
Ambient Air Temperature-to-operating Pressure Table
Trouble Diagnoses for Unusual Pressure
Whenever system
′s high and/or low side pressure is unusual, diagnose using a manifold gauge. The marker
above the gauge scale in the following tables indicate s the standard (usual) pressure range. Since the stan-
dard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air temperature-
to-operating pressure table).
Both High- and Low-pressure Sides are Too High
Vehicle location Indoors or in the shade (in a well-ventilated place)
Doors Closed
Door window Open
Hood Open
TEMP. Max. COLD
Mode switch (Ventilation) set
Recirculation (REC) switch (Recirculation) set
Blower speed Max. speed set
Engine speed Idle speed
Operate the air conditioning system for 10 minutes before taking measurements.
Inside air (Recirculating air) at blower assembly inlet Discharge air temperature at center ventilator
°C ( °F)
Relative humidity
% Air temperature
°C ( °F)
50 - 60 20 (68) 9.9 - 13.9 (50 - 57)
25 (77) 14.6 - 18.6 (58 - 65)
30 (86) 16.8 - 21.8 (62 - 71)
35 (95) 21.1 - 27.1 (70 - 81)
40 (104) 25.3 - 31.5 (78 - 89)
60 - 70 20 (68) 11.4 - 15.2 (53 - 59)
25 (77) 15.5 - 20.0 (60 - 68)
30 (86) 19.9 - 25.0 (68 - 77)
35 (95) 24.5 - 29.6 (76 - 85)
40 (104) 28.7 - 34.9 (84 - 95)
Ambient air High-pressure (Discharge side)
kPa (kg/cm
2 , psi) Low-pressure (Suction side)
kPa (kg/cm2 , psi)
Relative humidity
% Air temperature
°C ( °F)
50 - 70 20 (68)
1020 - 1250
(10.4 - 12.7, 147.9 - 181.3) 160 - 190
(1.63 - 1.94, 23.2 - 27.6)
25 (77) 1236 - 1510
(12.6 - 15.4, 179.2 - 219) 206 - 245
(2.1 - 2.5, 29.9 - 35.6)
30 (86) 1569 - 1,922
(16.0 - 19.6, 227.6 - 278.8) 265 - 324
(2.7 - 3.3, 38.4 - 46.9)
35 (95) 1,697 - 2079
(17.3 - 21.2, 246.1 - 301.5) 304 - 363
(3.1 - 3.7, 44.1 - 52.6)
40 (104) 1971 - 2403
(20.1 - 24.5, 285.9 - 348.5) 373 - 451
(3.8 - 4.6, 54.0 - 65.4)

ATC-106
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
High-pressure Side is Too High and Low-pressure Side is Too Low
High-pressure Side is Too Low and Low-pressure Side is Too High
Both High- and Low-pressure Sides are Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too high. Pressure is reduced soon af-
ter water is splashed on con-
denser.
Excessive refrigerant charge in
refrigeration cycle
Reduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is in-
sufficient. Insufficient condenser cooling
performance
↓
1. Condenser fins are
clogged.
2. Improper fan rotation of cooling fan • Clean condenser.
• Check and repair cooling fan
if necessary.
• Low-pressure pipe is not cold.
• When compressor is stopped high-pressure val-
ue quickly drops by approx-
imately 196 kPa (2 kg/cm
2 ,
28 psi). It then decreases
gradually thereafter. Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure decreas-
es too slowly.)
↓
Air in refrigeration cycle
Evacuate and recharge system.
Engine tends to overheat. Engine cooling systems mal-
function. Check and repair engine cool-
ing system.
• An area of the low-pressure pipe is colder than areas
near the evaporator outlet.
• Plates are sometimes cov- ered with frost. • Excessive liquid refrigerant
on low-pressure side
• Excessive refrigerant dis- charge flow
• Expansion valve is open a lit- tle compared with the speci-
fication.
↓
Improper expansion valve ad-
justment Replace expansion valve.
AC359A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high and
low-pressure side is too low.
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.High-pressure tu
be or parts lo-
cated between compressor
and condenser are clogged or
crushed. • Check and repair or replace
malfunctioning parts.
• Check oil for contamination.
AC360A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low and
low-pressure side is too high. High- and low-pressure sides
become equal soon after com-
pressor operation stops.Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.
Replace compressor.
No temperature difference be-
tween high- and low-pressure
sides. Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.
Replace compressor.
AC356A

TROUBLE DIAGNOSISATC-107
< SERVICE INFORMATION >
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Low-pressure Side Some
times Becomes Negative
Low-pressure Side Becomes Negative
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too low. • There is a big temperature
difference between liquid
tank outlet and inlet. Outlet
temperature is extremely
low.
• Liquid tank inlet and expan-
sion valve are frosted. Liquid tank inside is slightly
clogged.
• Replace liquid tank.
• Check oil for contamination.
• Temperature of expansion valve inlet is extremely low
as compared with areas
near liquid tank.
• Expansion valve inlet may be frosted.
• Temperature difference oc- curs somewhere in high-
pressure side. High-pressure pipe located be-
tween liquit tank and expan-
sion valve is clogged.
• Check and repair malfunc-
tioning parts.
• Check oil for contamination.
Expansion valve and liquid
tank are warm or only cool
when touched. Low refrigerant charge.
↓
Leaking fittings or compo-
nents.Check refrigerant system for
leaks. Refer to
ATC-166,
"Checking of Refrigerant
Leaks" .
There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted. Expansion valve closes a little
compared with the specifica-
tion.
↓
1. Improper expansion
valve adjustment.
2. Malfunctioning expansion
valve.
3. Outlet and inlet may be clogged. • Remove foreign particles by
using compressed air.
• Check oil for contamination.
An area of the low-pressure
pipe is colder than areas near
the evaporator outlet. Low-pressure pipe is clogged
or crushed.• Check and repair malfunc-
tioning parts.
• Check oil for contamination.
Air flow volume is too low. Evaporator is frozen. • Check intake sensor circuit.
Refer to ATC-120, "
Intake
Sensor Circuit" .
• Repair evaporator fins.
• Replace evaporator.
• Refer to AT C - 7 8 , "
Front
Blower Motor Circuit" .
AC353A
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side sometimes be-
comes negative. • Air conditioning system does
not function and does not cy-
clically cool the compart-
ment air.
• The system constantly func-
tions for a certain period of
time after compressor is
stopped and restarted. Refrigerant does not discharge
cyclically.
↓
Moisture is frozen at expan-
sion valve outlet and inlet.
↓
Water is mixed with refrigerant.
• Drain water from refrigerant
or replace refrigerant.
• Replace liquid tank.
AC354A

ATC-108
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Insufficient Heating
INFOID:0000000003533261
SYMPTOM: Insufficient heating
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPER ATIONAL CHECK - TEMPERATURE INCREASE
1. Press the AUTO switch.
2. Turn the temperature control dial (driver) clockwise until 32 ° C (90 ° F) is displayed.
3. Check for hot air at discharge air outlets.
Can this symptom be duplicated?
YES >> GO TO 2.
NO >> Perform complete system operational check. Refer to ATC-50, "
Operational Check (Front)" .
2.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 3.
3.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis. Refer to ATC-48, "
A/C System Self-Diagnosis Function" .
OK or NG
OK >> GO TO 4.
NG >> Refer to ATC-48, "
A/C System Self-Diagnosis Function" .
4.CHECK ENGINE COOLING SYSTEM
1. Check for proper engine coolant level. Refer to CO-9, "
Inspection".
2. Check hoses for leaks or kinks.
3. Check radiator cap. Refer to CO-9, "
Inspection" .
4. Check for air in cooling system.
>> GO TO 5.
5.CHECK AIR MIX DOOR OPERATION
Check the operation of the air mix door.
OK or NG
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side becomes nega-
tive. Liquid tank or front/rear side of
expansion valve′s pipe is frost-
ed or dewed. High-pressure side is closed
and refrigerant does not flow.
↓
Expansion valve or liquid tank
is frosted. Leave the system at rest until
no frost is present. Start it
again to check whether or not
the malfunction is caused by
water or foreign particles.
• If water is the cause, initially
cooling is okay. Then the wa-
ter freezes causing a block-
age. Drain water from
refrigerant or replace refrig-
erant.
• If due to foreign particles, re-
move expansion valve and
remove the particles with dry
and compressed air (not
shop air).
• If either of the above meth- ods cannot correct the mal-
function, replace expansion
valve.
• Replace liquid tank.
• Check oil for contamination.
AC362A

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