control INFINITI FX35 2004 Service Manual

ATC-72
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
Mode Door Control Specification
COMPONENT DESCRIPTION
Mode Door Motor
The mode door motor is attached to the heater & cooling unit. It
rotates so that air is discharged from the outlet set by the unified
meter and A/C amp. Motor rotation is conveyed to a link which acti-
vates the mode door.
DIAGNOSTIC PROCEDURE FOR MODE DOOR MOTOR
SYMPTOM: Mode door motor does not operate normally.
Perform diagnostic procedure for AT C - 6 6 , "
DIAGNOSTIC PROCEDURE FOR LAN CIRCUIT" .
RJIA1778E
RJIA0890E

ATC-74
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
SYSTEM DESCRIPTION
Component Parts
Air mix door control system components are:

Unified meter and A/C amp.

Air mix 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 LCU, mode door
motor LCU and intake door motor LCU.
The air mix door motor, 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 motor with the existing decision and opening
angles. Subsequently, HOT/COLD or DEFROST/VENT or FRESH/RECIRCULATION operation is selected.
The new selection data is returned to the unified meter and A/C amp.
Air Mix Door Control Specification
RJIA1781E
RJIA1782E

TROUBLE DIAGNOSIS
ATC-77
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2004 November 2004 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 DEFROST, or OFF switches are pushed 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
RJIA1786E
RJIA1787E

TROUBLE DIAGNOSIS
ATC-79
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2004 November 2004 FX35/FX45
Blower Motor CircuitAJS0014X
SYMPTOM:

Blower motor operation is malfunctioning.

Blower motor operation is malfunctioning under out of starting fan speed control.
INSPECTION FLOW
*1ATC-61, "Operational Check".*2AT C - 11 3 , "Intake Sensor Circuit".*3ATC-54, "FUNCTION CONFIRMA-
TION PROCEDURE", see No.4.
*4ATC-54, "
FUNCTION CONFIRMA-
TION PROCEDURE", see No.6.*5AT C - 5 4 , "
FUNCTION CONFIRMA-
TION PROCEDURE", see No.13.*6ATC-81, "
DIAGNOSTIC PROCE-
DURE FOR BLOWER MOTOR".
RJIA1994E

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-81
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2004 November 2004 FX35/FX45
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 low speed until the engine coolant temperature rises above
56°C (133°F), at which time 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 AUTO switch is pushed. The blower speed will gradually
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. During conditions of low or no sunload, the blower
low speed is usual low speed (duty ratio 25%). During high sunload conditions, the unified meter and A/C
amp. causes the blower speed to increase (duty ratio 49%).
Fan Speed Control Specification
COMPONENT DESCRIPTION
Brush-less Motor
The blower motor utilizes a brush-less motor with a rotating magnet.
Quietness is improved over previous motors where the brush was
the point of contact and the coil rotated.
DIAGNOSTIC PROCEDURE FOR BLOWER MOTOR
SYMPTOM: Blower motor operation is malfunctioning under starting
fan speed control.
RJIA1996E
ZHA152H
SJIA0266E

TROUBLE DIAGNOSIS
ATC-85
C
D
E
F
G
H
I
K
L
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-98
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
Low-pressure Side Sometimes Becomes Negative
Low-pressure Side Becomes Negative
DIAGNOSTIC 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 harness connector F6 ter-
minal 2 (G) 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-83, "
FUSE
BLOCK - JUNCTION BOX (J/B)" .
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 dewed.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

TROUBLE DIAGNOSIS
ATC-99
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2004 November 2004 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 3 , "
Self-diagnosis Func-
tion" .
4. Set in self-diagnosis STEP-45. Refer to AT C - 5 4 , "
FUNCTION
CONFIRMATION PROCEDURE" .
5. Confirm the unified meter and A/C amp. harness connector M57
terminal 45 (PU/W) duty ratio using an oscilloscope.
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 (PU) and unified meter and A/C amp. harness
connector M57 terminal 45 (PU/W).
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
RJIA1475E
3 – 45 : Continuity should exist.
RJIA2296E
2 – 3 : Continuity should exist.
RJIA2297E

CONTROLLER
ATC-115
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2004 November 2004 FX35/FX45
CONTROLLERPFP:27500
Removal and Installation of A/C and AV SwitchAJS001BN
REMOVAL
Remove cluster lid C. Refer to IP-11, "Removal and Installation" .
INSTALLATION
Installation is basically the reverse order of removal.