2005 INFINITI FX35 cooling

TROUBLE DIAGNOSIS ATC-91
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Revision: 2005 July 2005 FX
Insufficient CoolingAJS0014Z
SYMPTOM: Insufficient cooling
INSPECTION FLOW
RJIA3005E

ATC-96
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
TROUBLE DIAGNOSIS FOR UNUSUAL PRESSURE
Whenever system’s high and/or low side pressure(s) is/are unusual, diagnose using a manifold gauge. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the
standard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air tempera-
ture-to-operating pressure table).
Both High- and Low-pressure Sides are Too High
High-pressure Side is Too High and Low-pressure Side is Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too high. Pressure is reduced soon
after water is splashed on
condenser. Excessive refrigerant charge
in refrigeration cycle. Reduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is
insufficient. Insufficient condenser cooling
performance.
↓
1. Condenser fins are clogged.
2. Improper fan rotation of cooling fan.

Clean condenser.

Check and repair cooling fan
as necessary.

Low-pressure pipe is not
cold.

When compressor is
stopped high-pressure
value quickly drops by
approximately 196 kPa (2
kg/cm
2 , 28 psi). It then
decreases gradually there-
after. Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure
decreases too slowly.)
↓
Air in refrigeration cycle. Evacuate repeatedly and
recharge system.
Engine tends to overheat. Engine cooling systems mal-
function. Check and repair each engine
cooling system.

An area of the low-pres-
sure 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
little compared with the
specification.
↓
Improper expansion valve
adjustment. 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 tube or parts
located between compressor
and condenser are clogged or
crushed.

Check and repair or replace
malfunctioning parts.

Check lubricant for contami-
nation.
AC360A

ATC-98
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
Low-pressure Side Sometimes Becomes Negative
Low-pressure Side Becomes Negative
DIAGNOSIS PROCEDURE FOR INSUFFICIENT COOLING
SYMPTOM: Insufficient cooling
1. CHECK POWER SUPPLY FOR ECV (ELECTRONIC CONTROL VALVE)
1. Disconnect compressor (ECV) connector.
2. Turn ignition switch ON.
3. Check voltage between compressor (ECV) harness connector F6 terminal 2 (G) and ground.
OK or NG
OK >> GO TO 2.
NG >> Check power supply circuit and 10 A fuse [No. 12, located in the fuse block (J/B)]. Refer to PG-82, "
FUSE
BLOCK - JUNCTION BOX (J/B)" .

If fuse is OK, check harness for open circuit. Repair or replace if necessary.

If fuse is NG, replace fuse and check harness for short circuit. Repair or replace if necessary.
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side sometimes
becomes negative.

Air conditioning system
does not function and does
not cyclically cool the com-
partment air.

The system constantly func-
tions for a certain period of
time after compressor is
stopped and restarted. Refrigerant does not dis-
charge cyclically.
↓
Moisture is frozen at expan-
sion valve outlet and inlet.
↓
Water is mixed with refriger-
ant.

Drain water from refrigerant
or replace refrigerant.

Replace liquid tank.
AC354A
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
frosted 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
water freezes causing a
blockage. Drain water from
refrigerant or replace refrig-
erant.

If due to foreign particles,
remove 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 lubricant for contami-
nation.
AC362A
2 – ground : Battery voltage
RJIA2294E

TROUBLE DIAGNOSIS ATC-107
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Revision: 2005 July 2005 FX
In-vehicle Sensor CircuitAJS00155
COMPONENT DESCRIPTION
In-vehicle Sensor
The in-vehicle sensor is located on instrument driver lower panel. It
converts variations in temperature of compartment air drawn from
the aspirator into a resistance value. It is then input into the unified
meter and A/C amp.
Aspirator
The aspirator is located on driver’s side of heater & cooling unit. It
produces vacuum pressure due to air discharged from the heater &
cooling unit, continuously taking compartment air in the aspirator.
RJIA2021E
RJIA0921E
RJIA1804E

TROUBLE DIAGNOSIS ATC-113
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Revision: 2005 July 2005 FX
Intake Sensor CircuitAJS00157
COMPONENT DESCRIPTION
Intake Sensor
The intake sensor is located on the heater & cooling unit assembly. It
converts temperature of air after it passes through the evaporator
into a resistance value which is then input to the unified meter and A/
C amp.
DIAGNOSIS PROCEDURE FOR INTAKE SENSOR
SYMPTOM: Intake sensor circuit is open or shorted. (24 or −24 is
indicated on unified meter and A/C amp. as a result of performing
self-diagnosis STEP-2.)
1. CHECK VOLTAGE BETWEEN INTAKE SENSOR AND GROUND
1. Disconnect intake sensor connector.
2. Turn ignition switch ON.
3. Check voltage between intake sensor harness connector M254 terminal 2 (R) and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
2. CHECK CIRCUIT CONTINUITY BETWEEN INTAKE SENSOR AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect unified meter and A/C amp. connector.
3. Check continuity between intake sensor harness connector M254 terminal 1 (W) and unified meter and A/C amp. harness
connector M57 terminal 49 (W/G).
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
RJIA0928E
RJIA1458E
2 – Ground : Approx. 5 V
RJIA2031E
1 – 49 : Continuity should exist.
RJIA2032E

ATC-126
HEATER & COOLING UNIT ASSEMBLY
Revision: 2005 July 2005 FX
HEATER & COOLING UNIT ASSEMBLYPFP:27110
Removal and InstallationAJS0015J
REMOVAL
1. Use a refrigerant collecting equipment (for HFC-134a) to discharge refrigerant.
2. Drain coolant from cooling system. Refer to CO-11, "
Changing Engine Coolant" (VQ35DE) or CO-37,
"Changing Engine Coolant" (VK45DE).
3. Remove cowl top cover. Refer to EI-23, "
COWL TOP" .
4. Remove high-pressure pipe 2 mounting clip.
5. Remove low-pressure flexible hose bracket mounting bolt.
6. Disconnect low-pressure pipe 1 and high-pressure pipe 2 from evaporator.
a. Set a disconnector [High-pressure side (SST: 9253089908), Low-pressure side (SST: 9253089916)] on A/C piping.
b. Slide a disconnector toward vehicle front until it clicks.
c. Slide A/C piping toward vehicle front and disconnect it. CAUTION:
Cap or wrap the joint of the pipe with suitable material such
as vinyl tape to avoid the entry of air.
7. Remove electric throttle control actuator (VQ35DE). Refer to EM-19, "
INTAKE MANIFOLD COLLECTOR" .
8. Disconnect two heater hoses from heater core.
9. Remove instrument panel assembly. Refer to IP-11, "
Removal
and Installation" .
10. Remove blower unit. Refer to ATC-121, "
BLOWER UNIT" .
RJIA2037E
RJIA2041E
RJIA2077E

HEATER & COOLING UNIT ASSEMBLY ATC-127
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Revision: 2005 July 2005 FX
11. Remove mounting nuts and bolts, and then remove instrument stays (left and right side).
12. Remove mounting bolts from heater & cooling unit assembly.
13. Disconnect drain hose.
14. Remove ventilator ducts, defroster nozzle and ducts.
15. Remove steering member mounting bolts, nut and harness clips.
16. Remove the steering member, and then remove heater & cooling unit assembly.
INSTALLATION
Installation is basically the reverse order of removal.
CAUTION:

Replace O-rings of A/C piping with new ones, and then apply compressor oil to it when installing
it.

Connection point for female-side piping is thin. So, when inserting male-side piping, take care not
to deform female-side piping. Slowly insert in axial direction.

Insert one-touch joint connection point securely until it clicks.

After piping has been connected, pull male-side piping by hand to make sure piping does not
come off.
RJIA2042E
RJIA2044E
RJIA2043E

ATC-128
HEATER & COOLING UNIT ASSEMBLY
Revision: 2005 July 2005 FX

When recharging refrigerant, check for leaks.
NOTE:

When filling radiator with coolant, refer to CO-11, "Changing Engine Coolant" (VQ35DE) or CO-37,
"Changing Engine Coolant" (VK45DE).

Recharge the refrigerant.
Heater & cooling unit mounting bolt
Tightening torque : 6.8 N·m (0.69 kg-m, 60 in-lb)
Steering member mounting nut and bolt
Tightening torque : 12 N·m (1.2 kg-m, 9 fl-lb)