2008 INFINITI FX35 Cold Air Intake System

ATC-18
< SERVICE INFORMATION >
REFRIGERATION SYSTEM
Evaporator intake air temperature is less than 20°C (68 °F).
Engine is running at speeds less than 1,500 rpm.
This is because the V-6 compressor prov ides a means of “capacity” control.
2. The V-6 variable compressor provides refrigerant c ontrol under varying conditions. During cold winters, it
may not produce high refrigerant pressure discharge (compared to previous units) when used with air
conditioning systems.
3. A “clanking” sound may occasionally be heard during re frigerant charge. The sound indicates that the tilt
angle of the wobble (swash) plate has changed and is not a malfunction.
4. For air conditioning systems with the V-6 compresso r, the clutch remains engaged unless: the system
main switch, fan switch or ignition switch is tur ned OFF. When ambient (outside) temperatures are low or
when the amount of refrigerant is insufficient, t he clutch is disengaged to protect the compressor.
DESCRIPTION
General
The variable compressor is a swash plate type that c hanges piston stroke in response to the required cooling
capacity.
The tilt of the wobble (swash) plate allows the piston’ s stroke to change so that refrigerant discharge continu-
ously change from 14.5 to 184 cm
3 (0.885 to 11.228 cu in).
RJIA1260E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

ATC-24
< SERVICE INFORMATION >
AIR CONDITIONER CONTROL
AIR CONDITIONER CONTROL
Description of Air Conditioner LAN Control SystemINFOID:0000000001328167
The LAN (Local Area Network) syst em consists of unified meter and A/C amp., mode door motor, air mix door
motors and intake door motor.
A configuration of these component s is shown in the figure below.
System ConstructionINFOID:0000000001328168
A small network is constructed between the unifi ed meter and A/C amp., air mix door motors, mode door
motor and intake door motor. The unified meter and A/C amp. and motors are connected by data transmission
lines and motor power supply lines. The LAN network is built through the ground circuits of each door motor.
Addresses, motor opening angle signals, motor stop si gnals and error checking messages are all transmitted
through the data transmission lines connecting the unified meter and A/C amp. and each door motor.
The following functions are contained in LCUs built into the air mix door motors, the mode door motor and the
intake door motor.
 Address
 Motor opening angle signals
 Data transmission
 Motor stop and drive decision
 Opening angle sensor (PBR function)
 Comparison
 Decision (Unified meter and A/C amp. indicated value and motor opening angle comparison)
OPERATION
The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp.
sends mode door, air mix door and intake door opening angle data to the mode door motor LCU, air mix door
motor LCU and intake door motor LCU.
The mode door motor, air mix door motors and intake door motor read their respective signals according to the
address signal. Opening angle indication signals received from the unified meter and A/C amp. and each of
the motor position sensors is compared by the LCUs in each door motor with the existing decision and open-
ing angles. Subsequently, HOT/COLD, DEF/VENT and FRE/ REC operation is selected. The new selection
data is returned to the unified meter and A/C amp.
SJIA1609E
RJIA1747E
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3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

ATC-58
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
SYSTEM DESCRIPTION
Component Parts
Mode door control system components are:
 Unified meter and A/C amp.
 Mode 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 unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp.
sends air mix door, mode door and intake door opening angle data to the air mix door motor LCUs, mode door
motor LCU and intake door motor LCU.
The air mix door motors, mode door motor and intake door motor read their respective signals according to the
address signal. Opening angle indication signals received from the unified meter and A/C amp. and each of
the motor position sensors are compared by the LCUs in each door motor with the existing decision and open-
ing angles. Subsequently, HOT/COLD, DEF/VENT and FRE/ REC operation is selected. The new selection
data are returned to the unified meter and A/C amp.
Mode Door Control Specification
*1 ATC-29, "Discharge Air Flow"*2AT C - 5 0 , "Operational Check"*3ATC-43, "Self-Diagnosis Function",
see No. 4 to 6.
*4 ATC-86, "
Ambient Sensor Circuit"*5AT C - 8 8 , "In-vehicle Sensor Circuit"*6ATC-91, "Sunload Sensor Circuit"
*7 ATC-94, "Intake Sensor Circuit"*8AT C - 5 9 , "Air Mix Door Motor Circuit"*9ATC-43, "Self-Diagnosis Function",
see No. 13.
*10 ATC-54, "
LAN System Circuit"*11AT C - 11 3*12ATC-32, "How to Perform Trouble Di-
agnosis for Quick and Accurate Re-
pair"
SJIA1585E
RJIA1778E
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3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

TROUBLE DIAGNOSISATC-61
< SERVICE INFORMATION >
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 Sunload sensor
 Intake sensor
System Operation
The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp.
sends air mix door, mode door and intake door motor opening angle data to the air mix door motor LCUs,
mode door motor LCU and intake door motor LCU.
The air mix door motors, mode door motor and intake door motor read their respective signals according to the
address signal. Opening angle indication signals receiv ed from the unified meter and A/C amp. and each of
the motor position sensors are compared by the LCUs in each door motor with the existing decision and open-
ing angles. Subsequently, HOT/COLD, DEF/VENT and FRE/REC operation is selected. The new selection
data are returned to the unified meter and A/C amp.
Air Mix Door Control Specification
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.
RJIA1781E
RJIA1782E
RJIA0893E
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ATC-66
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
 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, sunl oad 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 automat ic air flow control, starting air flow control, low
water temperature starting control and high passenger co mpartment temperature starting control are avail-
able.
Starting Fan Speed Control
Start up from COLD SOAK Condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 56 °C (133 °F), the blower will not
operate for a short period of time (up to 150 seconds ). The exact start delay time varies depending on the
ambient and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described
above. After this delay, the blower will operate at lo w speed until the engine coolant temperature rises above
56 °C (133 °F), and then the blower speed will increase to the objective speed.
Start up from usual or HOT SOAK Condition (Automatic mode)
The blower will begin operation momentarily after the AU TO switch is pressed. The blower speed will gradu-
ally rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).
Blower Speed Compensation
Sunload
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low
speed. The low speed will vary depending on the sunload. Du ring conditions of low or no sunload, the blower
speed is at duty ratio 25%. During high sunload conditi ons, the unified meter and A/C amp. raise the blower
speed (duty ratio 49%).
Fan Speed Control Specification
RJIA1995E
RJIA1996E
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3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

ATC-78
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Test Reading
Recirculating-to-discharge Air Temperature Table
Ambient Air Temperature-to -operating Pressure Table
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
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)
Vehicle condition Indoors or in the shade (in a well-ventilated place)
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

ATC-80
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Low-pressure Side Sometimes 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 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 oc- curs somewhere in high-
pressure side. High-pressure pipe located be-
tween liquid tank and expan-
sion 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-138, "
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.
 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 - 9 4 , "
Intake
Sensor Circuit".
 Replace compressor.
 Repair evaporator fins.
 Replace evaporator.
Refer to AT C - 6 4 , "
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
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

REFRIGERANT LINESATC-141
< SERVICE INFORMATION >
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6. Do not stop when one leak is found. Continue to check for additional leaks at all system components.
If no leaks are found, perform steps 7 - 10.
7. Start the engine.
8. Set the A/C control as follows;
a. A/C switch: ON
b. Mode door position: VENT (Ventilation)
c. Intake position: Recirculation
d. Temperature setting: Max. cold
e. Fan speed: High
9. Run engine at 1,500 rpm for at least 2 minutes.
10. Stop the engine and perform leak check again following steps 4 through 6 above.
Refrigerant leaks should be chec ked immediately after stopping
the engine. Begin with the leak detector at the compressor. The
pressure on the high-pressure side will gradually drop after
refrigerant circulation stops and pressure on the low-pressure
side will gradually rise, as shown in the graph. Some leaks are
more easily detected when pressure is high.
11. Before connecting recovery/recycling recharging equipm ent to vehicle, check recovery/recycling recharg-
ing equipment gauges. No refrigerant pressure should be displayed. If pressure is displayed, recover
refrigerant from equipment lines and then check refrigerant purity.
12. Confirm refrigerant purity in supply tank using recovery/recycling recharging equipment and refrigerant
identifier.
13. Confirm refrigerant purity in vehicle A/C system us ing recovery/recycling recharging equipment and refrig-
erant identifier.
14. Discharge A/C system using approved refrigerant recove ry equipment. Repair the leaking fitting or com-
ponent if necessary.
15. Evacuate and recharge A/C system and perform the l eak test to confirm no refrigerant leaks.
16. Perform A/C performance test to ensure system works properly.
SHA839E
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3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C