Ac system INFINITI FX35 2006 Service Manual

ATC-74
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
Intake Door Motor CircuitNJS000E7
SYMPTOM

Intake door does not change.

Intake door motor does not operate normally.
INSPECTION FLOW
*1 AT C - 5 3 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6. *2
ATC-103, "
Ambient Sensor Circuit"*3 ATC-106, "In-vehicle Sensor Circuit"
*4 ATC-109, "Sunload Sensor Circuit"*5AT C - 7 1 , "Air Mix Door Motor Circuit"*6 AT C - 5 3 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*7 AT C - 6 4 , "
LAN System Circuit"*8ATC-123, "INTAKE DOOR MOTOR"*9 AT C - 6 0 , "Operational Check"
*10 AT C - 4 1 , "SYMPTOM TABLE"*11AT C - 11 2 , "Intake Sensor Circuit"
SJIA1587E

TROUBLE DIAGNOSIS ATC-75
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Revision: 2006 December 2006 FX35/FX45
SYSTEM DESCRIPTION
Component Parts
Intake door control system components are:

Unified meter and A/C amp.

Intake door motor (LCU)

A/C LAN system (PBR built-in mode door motor, air mix door motor and intake door motor)

In-vehicle sensor

Ambient sensor

Sunload sensor

Intake sensor
System Operation
The intake door control determines intake door position based on the ambient temperature, the intake air tem-
perature and the in-vehicle temperature. When the DEF, or OFF switches are pressed or A/C switch is OFF,
the unified meter and A/C amp. sets the intake door at the FRESH position.
Intake Door Control Specification
SJIA1588E
RJIA1787E

ATC-78
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
SYSTEM DESCRIPTION
Component Parts
Fan speed control system components are:

Unified meter and A/C amp.

A/C LAN system (PBR built-in mode door motor, air mix door motor and intake door motor)

In-vehicle sensor

Ambient sensor

Sunload sensor

Intake sensor
System Operation
Automatic Mode
In the automatic mode, the blower motor speed is calculated by the unified meter and A/C amp. based on the
input from the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor.
When the air flow is increased, the duty ratio of the blower fan motor’s drive signal is changed at 8%/sec. to
prevent a sudden increase in air flow.
In addition to manual air flow control and the usual automatic air flow control, starting air flow control, low
water temperature starting control and high passenger compartment temperature starting control are avail-
able.
RJIA1995E

TROUBLE DIAGNOSIS ATC-83
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Revision: 2006 December 2006 FX35/FX45
SYSTEM DESCRIPTION
Unified meter and A/C amp. controls compressor operation by ambient temperature, intake air temperature
and signal from ECM.
Low Temperature Protection Control
Unified meter and A/C amp. will turn the compressor ON or OFF as determined by a signal detected by ambi-
ent sensor and intake sensor.
When ambient temperature is higher than −2 °C (28 °F), the compres-
sor turns ON. The compressor turns OFF when ambient temperature
is lower than −5 °C (23 °F).
When intake air temperature is higher than 1 °C (34 °F), the compres-
sor turns ON. The compressor turns OFF when intake air tempera-
ture is lower than −5°C (23 °F).
DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
RHA094GB
SJIA0267E
SJIA1608E

ATC-86
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
7. CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (COMPRESSOR ON SIGNAL)
1. Reconnect BCM connector and unified meter and A/C amp. connector.
2. Turn ignition switch ON.
3. Check voltage between unified meter and A/C amp. harness connector M57 terminal 42 and ground using an oscilloscope.
OK or NG
OK >> GO TO 8.
NG-1 >> If the voltage is approx. 5 V when A/C switch is ON: Replace unified meter and A/C amp.
NG-2 >> If the voltage is approx. 0 V when A/C switch is OFF: Replace BCM.
RJIA2007E
Terminals
Condition Voltage
(+)
( − )
Unified meter
and A/C amp. connector Terminal
No.
M57 42 Ground A/C switch: ON
(Blower motor operates.) Approx. 0 V
OFF switch: ON
(A/C system: OFF)
SJIA1423J

ATC-88
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
11 . CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (FAN ON SIGNAL)
1. Reconnect BCM connector and unified meter and A/C amp. connector.
2. Turn ignition switch ON.
3. Check voltage between unified meter and A/C amp. harness connector M57 terminal 57 and ground using an oscilloscope.
OK or NG
OK >> GO TO 12.
NG-1 >> If the voltage is approx. 5 V when blower motor is ON: Replace unified meter and A/C amp.
NG-2 >> If the voltage is approx. 0 V when blower motor is OFF: Replace BCM. Refer to BCS-15,
"Removal and Installation of BCM" .
12. CHECK CAN COMMUNICATION
Check CAN communication. Refer to BCS-14, "
CAN Communication Inspection Using CONSULT-II (Self-
Diagnosis)" .

BCM – ECM

ECM – IPDM E/R

ECM – Unified meter and A/C amp.
OK or NG
OK >> Replace ECM
NG >> Repair or replace malfunctioning part(s).
RJIA2010E
Terminals
Condition Voltage
(+)
(-)
Unified meter
and A/C amp. connector Terminal No.
M57 57 Ground A/C switch: ON
(Blower motor operates.) Approx. 0 V
OFF switch: ON
(A/C system: OFF)
SJIA1474J

TROUBLE DIAGNOSIS ATC-91
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Revision: 2006 December 2006 FX35/FX45
*1 ATC-53, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6. *2
ATC-71, "
Air Mix Door Motor Circuit"*3ATC-94, "Test Reading"
*4 ATC-58, "AUXILIARY MECHA-
NISM: TEMPERATURE SETTING
TRIMMER"
*5ATC-53, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13. *6
ATC-64, "
LAN System Circuit"
*7 ATC-77, "Blower Motor Circuit"*8ATC-82, "Magnet Clutch Circuit"*9ATC-92, "PERFORMANCE TEST
DIAGNOSIS"
*10 ATC-60, "Operational Check"*11AT C - 7 , "CONTAMINATED REFRIG-
ERANT"
*12EM-15, "Checking Drive Belts"
(VQ35DE) or EM-174, "
Checking
Drive Belts" (VK45DE)
*13 EC-497, "
SYSTEM DESCRIPTION"
(VQ35DE) or EC-1171, "
SYSTEM
DESCRIPTION" (VK45DE)

ATC-94
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
PERFORMANCE CHART
Test Condition
Testing must be performed as follows:
Test Reading
Recirculating-to-discharge Air Temperature Table
Ambient Air Temperature-to-operating Pressure Table
Vehicle condition Indoors or in the shade (in a well-ventilated place)
Doors Closed
Door windows Open
Hood Open
TEMP. Max. COLD
Mode switch (Ventilation) set
Intake switch (Recirculation) set
Fan (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) 11.2 - 13.2 (52 - 56)
25 (77) 12.2 - 14.8 (54 - 59)
30 (86) 15.5 - 18.6 (60 - 65)
35 (95) 21.0 - 24.5 (70 - 76)
40 (104) 28.7 - 32.6 (84 - 91)
60 - 70 20 (68) 13.2 - 15.2 (56 - 59)
25 (77) 14.8 - 17.3 (59 - 63)
30 (86) 18.6 - 21.6 (65 - 71)
35 (95) 24.5 - 28.0 (76 - 82)
40 (104) 32.6 - 36.5 (91 - 98)
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)
961 - 1,167
(9.8 - 11.9, 139 - 169) 216 - 265
(2.2 - 2.7, 31 - 38)
25 (77) 1,108 - 1,353
(11.3 - 13.8, 161 - 196) 230 - 281
(2.3 - 2.9, 33 - 41)
30 (86) 1,275 - 1,549
(13.0 - 15.8, 185 - 225) 261 - 320
(2.7 - 3.3, 38 - 46)
35 (95) 1,549 - 1,893
(15.8 - 19.3, 225 - 274) 297 - 364
(3.0 - 3.7, 43 - 53)
40 (104) 1,814 - 2,216
(18.5 - 22.6, 263 - 321) 357 - 435
(3.6 - 4.4, 52 - 63)

TROUBLE DIAGNOSIS ATC-95
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Revision: 2006 December 2006 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

TROUBLE DIAGNOSIS ATC-97
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Revision: 2006 December 2006 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-81, "
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