INFINITI FX35 2007 Service Manual

TROUBLE DIAGNOSIS ATC-95
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Revision: 2006 July 2007 FX35/FX45
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-96
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
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
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
between high- and low-pres-
sure sides. Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings. Replace compressor.
AC356A
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 lubricant for contami-
nation.

Temperature of expansion
valve inlet is extremely low
as compared with areas
near liquid tank.

Expansion valve inlet is
frosted.

Temperature difference
occurs somewhere in high-
pressure side. High-pressure pipe located
between liquid tank and
expansion valve is clogged.

Check and repair malfunc-
tioning parts.

Check lubricant for contami-
nation.
Expansion valve and liquid
tank are warm or slightly cool
when touched. Low refrigerant charge.
↓
Leaking fittings or compo-
nents. Check refrigerant for leaks.
Refer to ATC-156, "
Checking
for 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.

Replace expansion valve.

Check lubricant for contami-
nation.
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 lubricant for contami-
nation.
Air flow volume is not enough
or is too low. Evaporator is frozen.

Check intake sensor circuit.
Refer to AT C - 11 2 , "
Intake
Sensor Circuit" .

Replace compressor.

Repair evaporator fins.

Replace evaporator.

Refer to AT C - 7 7 , "Blower
Motor Circuit" .
AC353A

TROUBLE DIAGNOSIS ATC-97
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Revision: 2006 July 2007 FX35/FX45
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 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-80, "
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
RJIA2294E

ATC-98
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
2. CHECK ECV CONTROL SIGNAL
1. Turn ignition switch OFF.
2. Reconnect compressor (ECV) connector.
3. Perform self-diagnosis. Refer to AT C - 5 2 , "
Self-diagnosis Func-
tion" .
4. Set in self-diagnosis STEP-4 (Code No. 45). Refer to AT C - 5 3 ,
"FUNCTION CONFIRMATION PROCEDURE" .
5. Confirm ECV control signal between unified meter and A/C amp. harness connector M57 terminal 45 and ground using an oscillo-
scope.
OK or NG
OK >> Replace compressor.
NG >> GO TO 3.
3. CHECK CIRCUIT CONTINUITY BETWEEN ECV AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect compressor (ECV) and unified meter and A/C amp. connector.
3. Check continuity between compressor (ECV) harness connector F6 terminal 3 and unified meter and A/C amp. harness connec-
tor M57 terminal 45.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK ECV
Check continuity between compressor (ECV) connector F6 terminals
2 and 3.
OK or NG
OK >> Replace unified meter and A/C amp.
NG >> Replace compressor.
RJIA2295E
SJIA1765E
3 – 45 : Continuity should exist.
RJIA2296E
2 – 3 : Continuity should exist.
RJIA2297E

TROUBLE DIAGNOSIS ATC-99
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Revision: 2006 July 2007 FX35/FX45
Insufficient HeatingNJS000EB
SYMPTOM: Insufficient heating
INSPECTION FLOW
*1ATC-60, "Operational Check"*2ATC-71, "Air Mix Door Motor Circuit"*3AT C - 5 3 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to
6.
*4 ATC-53, "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13. *5
ATC-64, "
LAN System Circuit"*6AT C - 7 7 , "Blower Motor Circuit"
*7 EC-209, "DTC P0117, P0118 ECT
SENSOR" (VQ35DE) or EC-880,
"DTC P0117, P0118 ECT SEN-
SOR" (VK45DE) *8
CO-11, "
Changing Engine Coolant"
(VQ35DE) or CO-38, "
Changing
Engine Coolant" (VK45DE) *9
CO-15, "
Checking Radiator Cap"
(VQ35DE) or CO-43, "
Checking
Radiator Cap" (VK45DE)
SJIA1593E

ATC-100
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
NoiseNJS000EC
SYMPTOM: Noise
INSPECTION FLOW
RJIA3108E

TROUBLE DIAGNOSIS ATC-101
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Revision: 2006 July 2007 FX35/FX45
Self-diagnosisNJS000ED
SYMPTOM: Self-diagnosis cannot be performed.
INSPECTION FLOW
*1 Compressor Clutch, ATC-142,
"REMOVAL"
*2 Compressor Clutch, ATC-144,
"INSTALLATION"
*3AT C - 2 7 , "Maintenance of Lubricant
Quantity in Compressor"
*4AT C - 6 0 , "Operational Check"*5EM-15, "Checking Drive Belts"
(VQ35DE) or EM-174, "
Checking
Drive Belts" (VK45DE)
*1 AT C - 6 0 , "
Operational Check"*2ATC-62, "Power Supply and Ground
Circuit for Auto Amp."
*3 AT C - 4 1 , "SYMPTOM TABLE"
SJIA1803E

ATC-102
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
Memory FunctionNJS000EE
SYMPTOM: Memory function does not operate.
INSPECTION FLOW
*1ATC-62, "Power Supply and Ground
Circuit for Auto Amp."
*2 ATC-60, "Operational Check"*3AT C - 5 3 , "FUNCTION CONFIRMA-
TION PROCEDURE"
SJIA1595E

TROUBLE DIAGNOSIS ATC-103
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Revision: 2006 July 2007 FX35/FX45
Ambient Sensor CircuitNJS000EF
COMPONENT DESCRIPTION
Ambient Sensor
The ambient sensor is attached on the hood lock stay. It detects
ambient temperature and converts it into a resistance value which is
then input into the unified meter and A/C amp.
AMBIENT TEMPERATURE INPUT PROCESS
The unified meter and A/C amp. includes a processing circuit for the ambient sensor input. However, when the
temperature detected by the ambient sensor increases quickly, the processing circuit retards the unified meter
and A/C amp. function. It only allows the unified meter and A/C amp. to recognize an ambient temperature
increase of 0.33 °C (0.6 °F) per 100 seconds.
As an example, consider stopping for a few minutes after high speed driving. Although the actual ambient tem-
perature has not changed, the temperature detected by the ambient sensor will increase. This is because the
heat from the engine compartment can radiate to the front grille area, location of the ambient sensor.
DIAGNOSIS PROCEDURE FOR AMBIENT SENSOR
SYMPTOM: Ambient sensor circuit is open or shorted. (21 or −21 is
indicated on unified meter and A/C amp. as a result of performing
self-diagnosis STEP-2.)
1. CHECK VOLTAGE BETWEEN AMBIENT SENSOR AND GROUND
1. Disconnect ambient sensor connector.
2. Turn ignition switch ON.
3. Check voltage between ambient sensor harness connector E34 terminal 1 and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
RJIA2016E
RJIA1461E
1 – Ground : Approx. 5 V
RJIA2017E

ATC-104
TROUBLE DIAGNOSIS
Revision: 2006 July 2007 FX35/FX45
2. CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT 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 ambient sensor harness connector E34 terminal 2 and unified meter and A/C amp. harness connec-
tor M57 terminal 49.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3. CHECK AMBIENT SENSOR
Refer to ATC-105, "
Ambient Sensor" .
OK or NG
OK >> 1. Replace unified meter and A/C amp. 2. Go to self-diagnosis AT C - 5 3 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
NG >> 1. Replace ambient sensor. 2. Go to self-diagnosis AT C - 5 3 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
4. CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT 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 ambient sensor harness connector E34 terminal 1 and unified meter and A/C amp. harness connec-
tor M57 terminal 39.
4. Check continuity between ambient sensor harness connector E34 terminal 1 and ground.
OK or NG
OK >> 1. Replace unified meter and A/C amp. 2. Go to self-diagnosis AT C - 5 3 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
NG >> Repair harness or connector. 2 – 49 : Continuity should exist.
RJIA2018E
1 – 39 : Continuity should exist.
1 – Ground : Continuity should not exist.
RJIA2019E