INFINITI FX35 2005 Service Manual

ATC-64
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
COMPONENT DESCRIPTION
Unified Meter and A/C Amp. (Automatic Amplifier)
The unified meter and A/C amp. has a built-in microcomputer which
processes information sent from various sensors needed for air con-
ditioner operation. The air mix door motor, mode door motor, intake
door motor, blower motor and compressor are then controlled.
When the various switches and temperature switch are operated,
data is input to the unified meter and A/C amp. from the display unit/
display control unit using CAN communication.
Self-diagnosis functions are also built into unified meter and A/C
amp. to provide quick check of malfunctions in the auto air condi-
tioner system.
Potentio Temperature Control (PTC)
The PTC is built into the A/C and AV switch. It can be set at an inter-
val of 0.5 °C (1.0 °F) in the 18 °C (60 °F) to 32 °C (90 °F) temperature
range by pressing temperature switch. The set temperature is dis-
played.
DIAGNOSIS PROCEDURE FOR A/C SYSTEM
SYMPTOM: A/C system does not come on.
RJIA1965E
RJIA1982E
RJIA1983E

TROUBLE DIAGNOSIS ATC-65
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Revision: 2005 July 2005 FX
1. CHECK POWER SUPPLY CIRCUIT FOR UNIFIED METER AND A/C AMP.
1. Disconnect unified meter and A/C amp. connector.
2. Check voltage between unified meter and A/C amp. harness connector M56 terminals 21 (R/W), 22 (G/R) and 35 (LG/R), uni-
fied meter and A/C amp. harness connector M57 terminal 46 (L/
W) and ground.
OK or NG
OK >> GO TO 2.
NG >> Check 10 A and 15 A fuses [Nos. 6, 10, 11, 12 and 19, located in the fuse block (J/B)]. Refer to
PG-82, "
FUSE BLOCK - JUNCTION BOX (J/B)" .

If fuses are OK, check harness for open circuit. Repair or replace if necessary.

If fuses are NG, replace fuse and check harness for short circuit. Repair or replace if necessary.
2. CHECK GROUND CIRCUIT FOR UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Check continuity between unified meter and A/C amp. harness connector M56 terminal 29 (B), 30 (B) and ground.
OK or NG
OK >> Replace unified meter and A/C amp.
NG >> Repair harness or connector.
Terminals Ignition switch position
(+)
(-) OFF ACC ON
Unified
meter and A/C amp.
connector Terminal No.
(wire color)
M56 21 (R/W)
Ground Battery volt-
age Battery volt-
age Battery
voltage
M56 22 (G/R) Approx. 0 V Approx. 0 V Battery
voltage
M56 35 (LG/R) Approx. 0 V Battery volt-
age Battery
voltage
M57 46 (L/W) Approx. 0 V Battery volt-
age Battery
voltage
RJIA1984E
29, 30 – Ground : Continuity should exist.
RJIA1985E

ATC-66
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
LAN System CircuitAJS0014S
SYMPTOM: Mode door motor, intake door motor and/or air mix door motor(s) does not operate normally.
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT
1. CHECK POWER SUPPLY FOR UNIFIED METER AND A/C AMP.
1. Turn ignition switch ON.
2. Check voltage between unified meter and A/C amp. harness connector M57 terminal 54 (Y/R) and ground.
OK or NG
OK >> GO TO 2.
NG >> Replace unified meter and A/C amp.
2. CHECK SIGNAL FOR UNIFIED METER AND A/C AMP.
Confirm A/C LAN signal between unified meter and A/C amp. har-
ness connector M57 terminal 43 (G/B) and ground using an oscillo-
scope.
OK or NG
OK >> GO TO 3.
NG >> Replace unified meter and A/C amp.
RJIA1775E
54 – Ground : Battery voltage
RJIA1986E
Terminals
Voltage
(+)
( − )
Unified meter and A/
C amp. connector Terminal No.
(wire color)
M57 43 (G/B) Ground
RJIA1987E
HAK0652D

TROUBLE DIAGNOSIS ATC-67
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Revision: 2005 July 2005 FX
3. CHECK POWER SUPPLY FOR EACH DOOR MOTOR
Check voltage between each door motor harness connector terminal
1 and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK SIGNAL FOR EACH DOOR MOTOR
Confirm A/C LAN signal between each door motor harness connec-
tor terminal 3 and ground using an oscilloscope.
OK or NG
OK >> GO TO 5.
NG >> Repair harness or connector.
5. CHECK MOTOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect each door motor connector.
3. Check continuity between each door motor harness connector terminal 2 and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector. 1 – Ground : Battery voltage
RJIA1988E
Door motor
Terminals
Voltage
(+)
( − )
Con-
nector Terminal
No.
(wire color)
Mode M258 3 (L)
Ground
Air mix
(Driver
side) M252 3 (L)
Air mix
(Passen-
ger side) M257 3 (L)
Intake M253 3 (L)
RJIA1989E
HAK0652D
2 – Ground : Continuity should exist.
RJIA1990E

ATC-68
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
6. CHECK MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect each door motor connector.
3. Reconnect each door motor connector.
4. Turn ignition switch ON.
5. Confirm operation of each door motor.
OK or NG
OK >> (Return to operate normally.)

Poor contact in motor connector.
NG >> (Does not operate normally.)

GO TO 7.
7. CHECK OPERATION OF AIR MIX DOOR MOTOR AND INTAKE DOOR MOTOR
1. Turn ignition switch OFF.
2. Disconnect mode, air mix (driver side, passenger side), and intake door motor connectors.
3. Reconnect air mix (driver side, passenger side) and intake door motor connectors.
4. Turn ignition switch ON.
5. Confirm operation of air mix door motor (driver side, passenger side) and intake door motor.
OK or NG
OK >> [Air mix (driver side, passenger side) and intake door motors operate normally.]

Replace mode door motor.
NG >> [Air mix (driver side, passenger side) and intake door motors does not operate normally.]

GO TO 8.
8. CHECK OPERATION OF MODE DOOR MOTOR AND INTAKE DOOR MOTOR
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (driver side, passenger side) connectors.
3. Reconnect mode door motor connector.
4. Turn ignition switch ON.
5. Confirm operation of mode door motor and intake door motor.
OK or NG
OK >> (Mode and intake door motors operate normally.)

GO TO 10.
NG >> (Mode and intake door motors does not operate normally.)

GO TO 9.
9. CHECK OPERATION OF MODE DOOR MOTOR AND AIR MIX DOOR MOTOR
1. Turn ignition switch OFF.
2. Disconnect intake door motor connector.
3. Reconnect air mix door motor (driver side, passenger side) connectors.
4. Turn ignition switch ON.
5. Confirm operation of mode door motor and air mix door motor (driver side, passenger side).
OK or NG
OK >> [Mode and air mix door motor (driver side, passenger side) operate normally.]

Replace intake door motor.
NG >> [Mode and air mix door motor (driver side, passenger side) does not operate normally.]

Replace display and A/C auto amp.

TROUBLE DIAGNOSIS ATC-69
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10. CHECK OPERATION OF AIR MIX DOOR MOTOR
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (driver side) connector.
3. Turn ignition switch ON.
4. Confirm operation of air mix door motor (passenger side).
OK or NG
OK >> [Air mix door motor (passenger side) operates normally.]

Replace air mix door motor (driver side).
NG >> [Air mix door motor (passenger side) does not operate normally.]

Replace air mix door motor (passenger side).

ATC-70
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
Mode Door Motor CircuitAJS0014T
SYMPTOM:

Air outlet does not change.

Mode door motor does not operate normally.
INSPECTION FLOW
*1AT C - 3 7 , "Discharge Air Flow"*2ATC-61, "Operational Check"*3ATC-113, "Intake Sensor Circuit"
*4 AT C - 5 4 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6. *5
ATC-104, "
Ambient Sensor Circuit"*6ATC-107, "In-vehicle Sensor Circuit"
*7 AT C - 11 0 , "Sunload Sensor Circuit"*8ATC-73, "Air Mix Door Motor Cir-
cuit"
*9ATC-54, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*10 AT C - 6 6 , "
DIAGNOSIS PROCE-
DURE FOR LAN CIRCUIT"
*11ATC-131, "MODE DOOR MOTOR"*12ATC-42, "SYMPTOM TABLE"
RJIA1991E

TROUBLE DIAGNOSIS ATC-71
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Revision: 2005 July 2005 FX
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 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 door motor with the existing decision and open-
ing angles. Subsequently, HOT/COLD, DEF/VENT and FRESH/RECIRCULATION operation is selected. The
new selection data are returned to the unified meter and A/C amp.
RJIA1777E

ATC-72
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
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.
DIAGNOSIS PROCEDURE FOR MODE DOOR MOTOR
SYMPTOM: Mode door motor does not operate normally.
Perform diagnosis procedure. Refer to AT C - 6 6 , "
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT" .
RJIA1778E
RJIA0890E

TROUBLE DIAGNOSIS ATC-73
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Revision: 2005 July 2005 FX
Air Mix Door Motor CircuitAJS0014U
SYMPTOM:

Discharge air temperature does not change.

Air mix door motor does not operate normally.
INSPECTION FLOW
*1ATC-54, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6. *2
ATC-104, "
Ambient Sensor Circuit"*3 ATC-107, "In-vehicle Sensor Circuit"
*4ATC-110, "Sunload Sensor Circuit"*5ATC-73, "Air Mix Door Motor Circuit"*6 ATC-54, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*7 ATC-66, "
LAN System Circuit".*8 ATC-61, "Operational Check"*9ATC-42, "SYMPTOM TABLE"
*10ATC-113, "Intake Sensor Circuit"
SJIA0546E