2004 INFINITI FX35 air intake

ATC-78
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
COMPONENT DESCRIPTION
Intake Door Motor
The intake door motor is attached to the intake 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.
DIAGNOSTIC PROCEDURE FOR INTAKE DOOR MOTOR
SYMPTOM: Intake door motor does not operate normally.
Perform diagnostic procedure for AT C - 6 6 , "
DIAGNOSTIC PROCEDURE FOR LAN CIRCUIT" .
RJIA0897E

ATC-80
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 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
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.
*7AT C - 4 2 , "SYMPTOM TABLE".*8ATC-104, "Ambient Sensor Circuit".*9ATC-107, "In-vehicle Sensor Cir-
cuit".
*10AT C - 11 0 , "
Sunload Sensor Circuit".*11EC-185, "DTC P0117, P0118 ECT
SENSOR" (VQ35DE) or EC-842,
"DTC P0117, P0118 ECT SEN-
SOR" (VK45DE).
RJIA1995E

TROUBLE DIAGNOSIS
ATC-85
C
D
E
F
G
H
I
K
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MA
B
AT C
Revision: 2004 November 2004 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).
DIAGNOSTIC PROCEDURE FOR MAGNET CLUTCH
SYMPTOM: Magnet clutch does not engage when A/C switch is ON.
RHA094GB
SJIA0267E
RJIA2003E

ATC-86
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
1. CHECK INTAKE SENSOR CIRCUIT
Check ambient sensor and intake sensor. Refer to AT C - 5 4 , "
FUNCTION CONFIRMATION PROCEDURE" ,
see No. 9 and 11.
OK or NG
OK >> GO TO 2.
NG >>

Malfunctioning ambient sensor: Refer to ATC-104, "Ambient Sensor Circuit" .

Malfunctioning intake sensor: Refer to AT C - 11 3 , "Intake Sensor Circuit" .
2. PERFORM AUTO ACTIVE TEST
Refer to PG-24, "
Auto Active Test" .
Does the magnet clutch operate?
YES >>
WITH CONSULT-II
GO TO 5.

WITHOUT CONSULT-II
GO TO 6.
NO >> Check 10A fuse (No. 79, located in IPDM E/R), 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 (magnet
clutch) connector.
3. Check continuity between IPDM E/R harness connector E8 ter-
minal 33 (L) and compressor harness connector F2 terminal 1
(L).
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 >> Replace IPDM E/R.
NG >> Replace magnet clutch. Refer to ATC-143, "
Removal
and Installation of Compressor Clutch" .
33 – 1 : Continuity should exist.
RJIA2004E
RJIA2005E

TROUBLE DIAGNOSIS
ATC-97
C
D
E
F
G
H
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K
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MA
B
AT C
Revision: 2004 November 2004 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
packingsReplace compressor.
No temperature difference
between high- and low-pres-
sure sidesCompressor 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 receiver
drier 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 may
be frosted.

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

Check and repair malfunc-
tioning parts.

Check lubricant for contami-
nation.
Expansion valve and liquid
tank are warm or only cool
when touched.Low refrigerant charge
↓
Leaking fittings or componentsCheck refrigerant for leaks.
Refer to ATC-157, "
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.

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 3 , "
Intake
Sensor Circuit" .

Replace compressor.
AC353A

ATC-102
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
Self-diagnosisAJS00152
SYMPTOM: Self-diagnosis cannot be performed.
INSPECTION FLOW
*1 Compressor Clutch, ATC-143,
"REMOVAL" .*2 Compressor Clutch, ATC-145, "INSTALLATION" .*3AT C - 2 7 , "
Maintenance of Lubricant
Quantity in Compressor".
*4ATC-61, "
Operational Check".*5EM-15, "Checking Drive Belts"
(VQ35DE) or EM-169, "
Checking
Drive Belts" (VK45DE).
*1ATC-63, "
Power Supply and Ground
Circuit for Auto Amp.".*2ATC-104, "
Ambient Sensor Circuit".*3ATC-107, "In-vehicle Sensor Circuit".
*4ATC-110, "
Sunload Sensor Circuit".*5ATC-113, "Intake Sensor Circuit".*6AT C - 7 5 , "Air Mix Door Motor PBR
Circuit".
*7ATC-61, "
Operational Check".*8ATC-42, "SYMPTOM TABLE".
RJIA2014E

TROUBLE DIAGNOSIS
ATC-113
C
D
E
F
G
H
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MA
B
AT C
Revision: 2004 November 2004 FX35/FX45
Intake Sensor CircuitAJS00157
COMPONENT DESCRIPTION
Intake Sensor
The intake sensor is located on the heater & cooling unit. It converts
temperature of air after it passes through the evaporator into a resis-
tance value which is then input to the unified meter and A/C amp.
DIAGNOSTIC 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 M254
terminal 2 (R) 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 (W) and unified meter and A/C amp. harness
connector M57 terminal 49 (W/G).
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
RJIA0928E
RJIA1458E
2 – Ground : Approx. 5V
RJIA2031E
1 – 49 : Continuity should exist.
RJIA2032E

ATC-114
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
3. CHECK INTAKE SENSOR
Refer to AT C - 11 4 , "
Intake Sensor" .
OK or NG
OK >> 1. Replace unified meter and A/C amp.
2. Go to self-diagnosis AT C - 5 4 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
NG >> 1. Replace intake sensor.
2. Go to self-diagnosis AT C - 5 4 , "
FUNCTION CONFIRMATION PROCEDURE" 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 (R) and unified meter and A/C amp. harness
connector M57 terminal 41 (P).
4. Check continuity between intake sensor harness connector
M254 terminal 2 (R) and ground.
OK or NG
OK >> 1. Replace unified meter and A/C amp.
2. Go to self-diagnosis AT C - 5 4 , "
FUNCTION CONFIRMATION PROCEDURE" and perform self-
diagnosis STEP-2. Confirm that code No. 20 is displayed.
NG >> Repair harness or connector.
COMPONENT INSPECTION
Intake Sensor
After disconnecting intake sensor connector M254, measure resis-
tance between terminals 1 and 2 at sensor side, using the table
below.
If NG, replace intake sensor.2 – 41 : Continuity should exist.
2 – Ground : Continuity should not exist.
RJIA2033E
Temperature °C (°F) Resistance kΩ
−15 (5) 12.34
−10 (14) 9.62
−5 (23) 7.56
0 (32) 6.00
5 (41) 4.80
10 (50) 3.87
15 (59) 3.15
20 (68) 2.57
25 (77) 2.12
30 (86) 1.76
35 (95) 1.47
40 (104) 1.23
45 (113) 1.04
RJIA2034E