2007 INFINITI QX56 low oil pressure

AT-188
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYMPTOMS
Check A/T fluid level. Refer to AT-13, "Checking Automatic Trans-
mission Fluid (ATF)".
OK or NG
OK >> GO TO 3.
NG >> Refill ATF.
3.CHECK LINE PRESSURE
Check line pressure at the engine stall point. Refer to AT-51,
"Inspections Before Trouble Diagnosis".
OK or NG
OK >> GO TO 6.
NG - 1 >> Line pressure high. GO TO 4.
NG - 2 >> Line pressure low. GO TO 5.
4.DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-210, "
Control Valve with TCM and A/T Fluid Temperature Sen-
sor 2".
2. Disassemble A/T. Refer to AT-240, "
Disassembly".
3. Check the following items:
- Oil pump assembly. Refer to AT-258, "
Oil Pump".
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
5.DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-210, "
Control Valve with TCM and A/T Fluid Temperature Sen-
sor 2".
2. Disassemble A/T. Refer to AT-240, "
Disassembly".
3. Check the following items:
- Oil pump assembly. Refer to AT-258, "
Oil Pump".
- Power train system. Refer to AT-240, "
Disassembly".
- Transmission case. Refer to AT-240, "
Disassembly".
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
6.CHECK A/T FLUID CONDITION
1. Remove oil pan. Refer to AT-210, "
Control Valve with TCM and A/T Fluid Temperature Sensor 2".
SAT638A
SAT494G

ATC-8
< SERVICE INFORMATION >
PRECAUTIONS
*: Always check with the Parts Department for the latest parts information.
WARNING:
Make sure all refrigerant is discharged into the recycling equipment and the pressure in the system is
less than atmospheric pressure. Then gradually loo sen the discharge side hose fitting and remove it.
CAUTION:
When replacing or cleaning refrigeran t cycle components, observe the following.
• When the compressor is removed, store it in the same position as it is when mounted on the car.
Failure to do so will cause oil to enter the low pressure chamber.
• When connecting tubes, always use a torque wrench and a back-up wrench.
• After disconnecting tubes, immedi ately plug all openings to prevent entry of dirt and moisture.
• When installing an air conditioner in the vehicle, connect the pipes as the final stage of the opera-
tion. Do not remove the seal caps of pipes and othe r components until just before required for con-
nection.
• Allow components stored in cool areas to warm to working area temperature before removing seal
caps. This prevents condensation from forming inside A/C components.
• Thoroughly remove moisture from the refrigerat ion system before charging the refrigerant.
• Always replace used O-rings.
• When connecting tube, apply oil to circle of the O-rings shown in illustration. Be careful not to apply
oil to threaded portion.
Oil name: NISSAN A/C System Oil Type S or equivalent
• O-ring must be closely attached to dented portion of tube.
• When replacing the O-ring, be careful not to damage O-ring and tube.
• Connect tube until you hear it cl ick, then tighten the nut or bolt by hand until snug. Make sure that
the O-ring is installed to tube correctly.
• After connecting line, conduct leak test and make sure that there is no leakage from connections.
When the gas leaking point is foun d, disconnect that line and replace the O-ring. Then tighten con-
nections of seal seat to the specified torque.
Connec-
tion typeO-ring
size Part number* D mm (in) W mm (in)
New 8 92471 N8210 6.8 (0.268) 1.85 (0.0728)
Former 10 J2476 89956 9.25 (0.3642) 1.78 (0.0701) New 1292472 N8210 10.9 (0.429) 2.43 (0.0957)
Former 92475 71L00 11.0 (0.433) 2.4 (0.094) New 1692473 N8210 13.6 (0.535) 2.43 (0.0957)
Former 92475 72L00 14.3 (0.563) 2.3 (0.091) New 1992474 N8210 16.5 (0.650) 2.43 (0.0957)
Former 92477 N8200 17.12 (0.6740) 1.78 (0.0701) New 24 92195 AH300 21.8 (0.858) 2.4 (0.094)
SHA814E

ATC-10
< SERVICE INFORMATION >
PRECAUTIONS
The oil contained inside the vacuum pump is not compatible with the
specified oil for HFC-134a (R-134a) A/C systems. The vent side of
the vacuum pump is exposed to atmospheric pressure so the vac-
uum pump oil may migrate out of the pump into the service hose.
This is possible when the pump is switched off after evacuation (vac-
uuming) and hose is connected to it.
To prevent this migration, use a manual valve situated near the
hose-to-pump connection, as follows.
• Usually vacuum pumps have a manual isolator valve as part of the
pump. Close this valve to isolat e the service hose from the pump.
• For pumps without an isolator, use a hose equipped with a manual shut-off valve near the pump end. Close the valve to isolate the
hose from the pump.
• If the hose has an automatic shut off valve, disconnect the hose from the pump: as long as the hose is connected, the valve is open
and lubricating oil may migrate.
Some one-way valves open when vacuum is applied and close
under a no vacuum condition. Such valves may restrict the pump's
ability to pull a deep vacuum and are not recommended.
MANIFOLD GAUGE SET
Be certain that the gauge face indicates HFC-134a (R-134a or
134a). Make sure the gauge set has 1/2 ″-16 ACME threaded con-
nections for service hoses. Confirm the set has been used only with
refrigerant HFC-134a (R-134a) along with specified oil.
SERVICE HOSES
Be certain that the service hoses display the markings described
(colored hose with black stripe). All hoses must include positive shut-
off devices (either manual or aut omatic) near the end of the hoses
opposite the manifold gauge.
SERVICE COUPLERS
RHA270D
SHA533D
RHA272D

ATC-16
< SERVICE INFORMATION >
REFRIGERATION SYSTEM
REFRIGERATION SYSTEM
Refrigerant CycleINFOID:0000000003533229
REFRIGERANT FLOW
The refrigerant flows in the standard pattern, that is, through the compressor, the condenser with liquid tank,
through the front and rear evaporators, and back to the compressor. The refrigerant evaporation through the
evaporator coils are controlled by front and rear exter nally equalized expansion valves, located inside the front
and rear evaporator cases.
Refrigerant System ProtectionINFOID:0000000003533230
REFRIGERANT PRESSURE SENSOR
The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure sen-
sor, located on the condenser. If the system pressure rise s above or falls below the specifications, the refriger-
ant pressure sensor detects the pressure inside t he refrigerant line and sends a voltage signal to the ECM.
The ECM de-energizes the A/C relay to disengage the magnetic compressor clutch when pressure on the high
pressure side detected by refrigerant pressu re sensor is over about 2,746 kPa (28 kg/cm
2, 398 psi), or below
about 120 kPa (1.22 kg/cm
2, 17.4 psi).
PRESSURE RELIEF VALVE
The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor.
When the pressure of refrigerant in the system incr eases to an abnormal level [more than 2,990 kPa (30.5 kg/

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 >
C
DE
F
G H
I
K L
M A
B
AT C
N
O P
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

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