air intake INFINITI FX35 2008 Owner's Manual

TROUBLE DIAGNOSISATC-63
< SERVICE INFORMATION >
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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
*1 AT C - 5 0 , "Operational Check"*2AT C - 4 3 , "Self-Diagnosis Function",
see No. 4 to 6. *3
AT C - 8 6 , "Ambient Sensor Circuit"
*4 AT C - 8 8 , "In-vehicle Sensor Circuit"*5AT C - 9 1 , "Sunload Sensor Circuit"*6 AT C - 9 4 , "Intake Sensor Circuit"
*7 AT C - 5 9 , "Air Mix Door Motor Circuit"*8AT C - 3 2 , "How to Perform Trouble
Diagnosis for Quick and Accurate
Repair"
*9 AT C - 4 3 , "Self-Diagnosis Function",
see No. 13.
*10 AT C - 5 4 , "
LAN System Circuit"*11AT C - 1 0 6
SJIA1807E
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ATC-64
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
 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 FRE position.
Intake Door Control Specification
COMPONENT DESCRIPTION
Intake Door Motor
The intake door motor is attached to the blower unit. It rotates so that
air is drawn from inlets set by the unified meter and A/C amp. Motor
rotation is conveyed to a lever which activates the intake door.
DIAGNOSIS PROCEDURE FOR INTAKE DOOR MOTOR
SYMPTOM: Intake door motor does not operate normally.
Perform diagnosis procedure. Refer to ATC-54, "
LAN System Circuit".
Blower Motor CircuitINFOID:0000000001328189
SYMPTOM: Blower motor operation is malfunctioning.
INSPECTION FLOW
SJIA1588E
RJIA1787E
RJIA0897E
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3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

TROUBLE DIAGNOSISATC-65
< SERVICE INFORMATION >
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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
*1 AT C - 5 0 , "Operational Check"*2AT C - 4 3 , "Self-Diagnosis Function",
see No. 4. *3
AT C - 4 3 , "Self-Diagnosis Function",
see No. 6.
*4 AT C - 8 6 , "
Ambient Sensor Circuit"*5AT C - 8 8 , "In-vehicle Sensor Circuit"*6 AT C - 9 1 , "Sunload Sensor Circuit"
*7AT C - 9 4 , "Intake Sensor Circuit"*8AT C - 3 2 , "How to Perform Trouble Di-
agnosis for Quick and Accurate Re-
pair"
*9 AT C - 4 3 , "Self-Diagnosis Function",
see No. 13.
*10 "DIAGNOSIS PROCEDURE FOR BLOWER MOTOR" *11
EC-193
(VQ35DE) or EC-779
(VK45DE)
SJIA1808E
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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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ATC-70
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
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.
1.CHECK AMBIENT SENSOR AND INTAKE SENSOR CIRCUIT
Check ambient sensor and intake sensor. Refer to ATC-43, "
Self-Diagnosis Function", see No. 9 and 11.
*4 "DIAGNOSIS PROCEDURE FOR
MAGNET CLUTCH" *5
AT C - 7 5 , "Insufficient Cooling"*6AT C - 5 0 , "Operational Check"
*7AT C - 4 3 , "Self-Diagnosis Function",
see No. 4 to 6. *8
AT C - 3 2 , "How to Perform Trouble Di-
agnosis for Quick and Accurate Re-
pair"
RHA094GB
SJIA0267E
SJIA1608E
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3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

TROUBLE DIAGNOSISATC-71
< SERVICE INFORMATION >
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OK or NG
OK >> GO TO 2.
NG >>  Malfunctioning ambient sensor: Refer to ATC-86, "
Ambient Sensor Circuit".
 Malfunctioning intake sensor: Refer to ATC-94, "
Intake Sensor Circuit".
2.PERFORM IPDM E/R AUTO ACTIVE TEST
Perform “IPDM E/R auto active test”. Refer to PG-20, "
Auto Active Test".
Does the magnet clutch operate?
YES >>  WITH CONSULT-III: GO TO 5  WITHOUT CONSULT-III: GO TO 6.
NO >> Check 10A fuse (No. 79, located in IPDM E/R). Refer to PG-23, "
IPDM E/R Terminal Arrange-
ment", and GO TO 3.
3.CHECK CIRCUIT CONTINUITY BETWEEN IPDM E/R AND COMPRESSOR
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R connector and compressor connector.
3. Check continuity between IPDM E/R harness connector E8 ter- minal 33 and compressor harness connector F2 terminal 1.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4.CHECK MAGNET CLUTCH CIRCUIT
Check for operation sound when applying battery voltage direct cur-
rent to terminal.
OK or NG
OK >> 1. Replace IPDM E/R. 2. Go to self-diagnosis procedure ATC-43, "
Self-Diag-
nosis Function" and perform self-diagnosis STEP-4.
Confirm that magnet clutch operation normal.
NG >> 1. Replace magnet clutch.
2. Go to self-diagnosis procedure ATC-43, "
Self-Diag-
nosis Function" and perform self-diagnosis STEP-4.
Confirm that magnet clutch operation normal.
5.CHECK BCM INPUT (COMPRESSOR ON) SIGNAL
Check compressor ON/OFF signal in “Data monitor”. Refer to ATC-32, "
CONSULT-III Function".
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.
6.CHECK CIRCUIT CONTINUITY BETWEEN BC M AND UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Disconnect BCM connector and unified meter and A/C amp. connector.
33 – 1 : Continui ty should exist.
RJIA2004E
RJIA2005E
A/C SW ON : AIR COND SW ON
A/C SW OFF : AIR COND SW OFF
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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)
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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
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ATC-94
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
 When checking sunload sensor, select a place where sunshine directly on it.
If NG, replace sunload sensor.
Intake Sensor CircuitINFOID:0000000001328199
COMPONENT DESCRIPTION
Intake Sensor
The intake sensor is located on t he 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 IN TAKE SENSOR AND GROUND
1. Disconnect intake sensor connector.
2. Turn ignition switch ON.
SHA930E
RJIA0928E
RJIA1458E
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TROUBLE DIAGNOSISATC-95
< SERVICE INFORMATION >
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3. Check voltage between intake sensor harness connector M254 terminal 2 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 and unified meter and A/C amp. harness con-
nector M57 terminal 49.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
3.CHECK INTAKE SENSOR
Refer to "Intake Sensor".
OK or NG
OK >> 1. Replace unified meter and A/C amp. 2. Go to self-diagnosis ATC-43, "
Self-Diagnosis Function" and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
NG >> 1. Replace intake sensor. 2. Go to self-diagnosis ATC-43, "
Self-Diagnosis Function" and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
4.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 2 and unified meter and A/C amp. harness con-
nector M57 terminal 41.
4. Check continuity between intake sensor harness connector M254 terminal 2 and ground.
OK or NG
OK >> 1. Replace unified meter and A/C amp. 2. Go to self-diagnosis ATC-43, "
Self-Diagnosis Function" and perform self-diagnosis STEP-2.
Confirm that code No. 20 is displayed.
NG >> Repair harness or connector.
COMPONENT INSPECTION
Intake Sensor
2 – Ground : Approx. 5 V
RJIA2031E
1 – 49 : Continuity should exist.
RJIA2032E
2 – 41 : Continuity should exist.
2 – Ground : Continuity should not exist.
RJIA2033E
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