2007 INFINITI M35 cooling

ATC-84
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
COMPONENT DESCRIPTION
Air Mix Door Motor
The air mix door motors are attached to the heater & cooling unit
assembly. It rotates so that the air mix door is opened or closed to a
position set by the unified meter and A/C amp. Motor rotation is then
conveyed through a shaft and the air mix door position feedback is
then sent to the unified meter and A/C amp. by PBR built-in air mix
door motor.
DIAGNOSIS PROCEDURE FOR AIR MIX DOOR MOTOR
SYMPTOM: Discharge air temperature does not change.
Perform diagnosis procedure. Refer to AT C - 7 1 , "
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
Air Mix Door Motor PBR CircuitNJS000GR
SYMPTOM

Discharge air temperature does not change.

PBR circuit is open or shorted.
DIAGNOSIS PROCEDURE FOR AIR MIX DOOR MOTOR PBR
Perform diagnosis procedure. Refer to AT C - 7 1 , "DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
RJIA4064E
RJIA4065E

ATC-98
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
Insufficient CoolingNJS000GV
SYMPTOM: Insufficient cooling
INSPECTION FLOW
SJIA1777E

ATC-104
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
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.The pressure returns to nor-
mal 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.

Low-pressure pipe is
sometimes covered 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-106
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
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
F34 terminal 2 and ground.
OK or NG
OK >> GO TO 2.
NG >> Check power supply circuit and 10A fuse [No. 12,
located in the fuse block (J/B)]. Refer to PG-114, "
FUSE
BLOCK - JUNCTION BOX (J/B)" .

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

If fuse is NG, check harness for short circuit and replace fuse.
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 wet with dew.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
RJIA4213E

TROUBLE DIAGNOSIS
ATC-115
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AT C
Revision: 2007 April2007 M35/M45
In-vehicle Sensor CircuitNJS000H1
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
assembly. It produces vacuum pressure due to air discharged from
the heater & cooling unit assembly, continuously taking compartment
air in the aspirator.
RJIA4092E
RJIA4093E
RJIA1804E

TROUBLE DIAGNOSIS
ATC-121
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AT C
Revision: 2007 April2007 M35/M45
Intake Sensor CircuitNJS000H3
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 M82
terminal 1 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 M82
terminal 2 and unified meter and A/C amp. harness connector
M65 terminal 59.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
RJIA4103E
RJIA4104E
1 – Ground : Approx. 5 V
RJIA4215E
2 – 59 : Continuity should exist.
RJIA4106E

ATC-134
HEATER & COOLING UNIT ASSEMBLY
Revision: 2007 April2007 M35/M45
HEATER & COOLING UNIT ASSEMBLYPFP:27110
Removal and InstallationNJS000HF
REMOVAL
1. Use a refrigerant collecting equipment (for HFC-134a) to discharge the refrigerant.
2. Drain coolant from cooling system. Refer to CO-11, "
Changing Engine Coolant" (VQ35DE) or CO-40,
"Changing Engine Coolant" (VK45DE).
3. Remove cowl top cover. Refer to EI-18, "
COWL TOP" .
4. Disconnect low-pressure flexible hose and high-pressure pipe 1
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 low-pressure flexible hose, low-
pressure pipe 1 and high-pressure pipe 1, 2 with suitable
material such as vinyl tape to avoid the entry of air.
5. Remove electric throttle control actuator. Refer to EM-21,
"INTAKE MANIFOLD COLLECTOR" (VQ35DE) or EM-179, "INTAKE MANIFOLD" (VK45DE).
6. Disconnect two heater hoses from heater core.
7. Remove instrument panel & pad. Refer to IP-10, "
INSTRUMENT PANEL ASSEMBLY" .
8. Remove blower unit. Refer to ATC-129, "
BLOWER UNIT" .
9. Remove clips of vehicle harness from steering member.
10. Remove mounting nuts and bolts, and then remove instrument stays.
RJIA4117E
RJIA4118E
RJIA4119E

HEATER & COOLING UNIT ASSEMBLY
ATC-135
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AT C
Revision: 2007 April2007 M35/M45
11. Disconnect drain hose.
12. Remove mounting bolts from heater & cooling unit.
13. Remove side defroster nozzles.
14. Remove steering column assembly mounting bolts and nut.
15. Remove steering member mounting bolts.
16. Remove steering member, and then remove heater & cooling unit.
INSTALLATION
Installation is basically the reverse order of removal.
RJIA4180E
RJIA4120E
SJIA1795E