INFINITI FX35 2004 Service Manual

ATC-62
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
CHECKING RECIRCULATION
1. Press recirculation (REC) switch one time. Recirculation indica-
tor should illuminate.
2. Press fresh (FRE) switch one time. Fresh indicator should illumi-
nate.
3. Listen for intake door position change (you should hear blower
sound change slightly).
If NG, go to trouble diagnosis procedure for AT C - 7 6 , "
Intake Door
Motor Circuit" .
If OK, continue the check.
NOTE:
Confirm that the compressor clutch is engaged (sound or visual
inspection) and intake door position is at FRESH when the DEF or D/F is selected.
CHECKING TEMPERATURE DECREASE
1. Press temperature (DOWN) switch (driver side) until 18°C
(60°F) is displayed.
2. Check for cold air at discharge air outlets.
If NG, go to trouble diagnosis procedure for AT C - 9 1 , "
Insufficient
Cooling" .
If OK, continue the check.
CHECKING TEMPERATURE INCREASE
1. Press temperature (UP) switch (driver side) until 32°C (90°F) is
displayed.
2. Check for hot air at discharge air outlets.
If NG, go to trouble diagnosis procedure for ATC-100, "
Insufficient
Heating" .
If OK, continue the check.
CHECK A/C SWITCH
1. Press AUTO switch and A/C switch.
2. A/C switch indicator will turn ON.

Confirm that the compressor clutch engages (sound or visual
inspection).
If NG, go to trouble diagnosis procedure for AT C - 8 4 , "
Magnet Clutch
Circuit" .
If OK, continue the check.
RJIA1978E
RJIA1976E
RJIA1977E
RJIA1975E

TROUBLE DIAGNOSIS
ATC-63
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AT C
Revision: 2004 November 2004 FX35/FX45
CHECKING AUTO MODE
1. Press AUTO switch and A/C switch.
2. Display should indicate AUTO.

Confirm that the compressor clutch engages (sound or visual
inspection). (Discharge air and blower speed will depend on
ambient, in-vehicle, and set temperatures.)
If NG, go to trouble diagnosis procedure for AT C - 6 3 , "
Power Supply
and Ground Circuit for Auto Amp." , then if necessary, trouble diag-
nosis procedure for AT C - 8 4 , "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go
to malfunction Simulation Tests in GI-27, "
How to Perform Efficient
Diagnosis for an Electrical Incident" and perform tests as outlined to
simulate driving conditions environment. If symptom appears, refer
to AT C - 4 2 , "
SYMPTOM TABLE" and perform applicable trouble diagnosis procedures.
Power Supply and Ground Circuit for Auto Amp.AJS001BF
SYMPTOM: A/C system does not come on.
INSPECTION FLOW
RJIA1979E
*1AT C - 6 4 , "DIAGNOSTIC PROCE-
DURE FOR A/C SYSTEM".*2ATC-61, "
Operational Check".*3AV- 7 8 , "Trouble Diagnosis Chart by
Symptom".
*4AV- 8 4 , "
A/C and AV Switch Does Not
Operate".
RJIA1980E

ATC-64
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
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.
The unified meter and A/C amp. is unitized with control mechanisms.
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 C/U using CAN communication.
Self-diagnostic 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.
DIAGNOSTIC PROCEDURE FOR A/C SYSTEM
SYMPTOM: A/C system does not come on.
RJIA1965E
RJIA1982E
RJIA1983E

TROUBLE DIAGNOSIS
ATC-65
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AT C
Revision: 2004 November 2004 FX35/FX45
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 10A and 15A fuses [Nos. 6, 10, 11, 12 and 19, located in the fuse block (J/B)]. Refer to PG-
83, "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.
connectorTerminal No.
(wire color)
M56 21 (R/W)
GroundBattery
voltageBattery
voltageBattery
voltage
M56 22 (G/R) Approx. 0V Approx. 0VBattery
voltage
M56 35 (LG/R) Approx. 0VBattery
voltageBattery
voltage
M57 46 (L/W) Approx. 0VBattery
voltageBattery
voltage
RJIA1984E
29, 30 – Ground : Continuity should exist.
RJIA1985E

ATC-66
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
LAN System CircuitAJS0014S
SYMPTOM: Mode door motor, intake door motor and/or air mix door motor(s) does not operate normally.
DIAGNOSTIC 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. connectorTerminal No.
(wire color)
M57 43 (G/B) Ground
RJIA1987E
HAK0652D

TROUBLE DIAGNOSIS
ATC-67
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AT C
Revision: 2004 November 2004 FX35/FX45
3. CHECK POWER SUPPLY FOR MOTOR
Check voltage between mode door motor harness connector M258
terminal 1 (G), driver side air mix door motor harness connector
M252 terminal 1 (G), passenger side air mix door motor harness
connector M257 terminal 1 (G), intake door motor harness connector
M253 terminal 1 (G) and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK SIGNAL FOR MOTOR
Confirm A/C LAN signal between mode door motor harness connec-
tor M258 terminal 3 (L), driver side air mix door motor harness con-
nector M252 terminal 3 (L), passenger side air mix door motor
harness connector M257 terminal 3 (L), intake door motor harness
connector M253 terminal 3 (G/B) 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 door motor connector.
3. Check continuity between mode door motor harness connector
M258 terminal 2 (B), driver side air mix door motor harness con-
nector M252 terminal 2 (B), passenger side air mix door motor
harness connector M257 terminal 2 (B), intake door motor har-
ness connector M253 terminal 2 (B) and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.1 – Ground : Battery voltage
RJIA1988E
Door motorTerminals
Voltage (+)
(−)
Con-
nectorTerminal
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: 2004 November 2004 FX35/FX45
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 each door motor operation.
OK or NG
OK >> (Return to operate normally.)

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

GO TO 7.
7. CHECK MODE DOOR MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect mode door motor and air mix door motor (driver side, passenger side) connector.
3. Reconnect mode door motor connector.
4. Turn ignition switch ON.
5. Confirm the mode door motor operation.
OK or NG
OK >> (Mode door motor operates normally.)

GO TO 8.
NG >> (Mode door motor does not operate normally.)

Repair mode door motor.
8. CHECK AIR MIX DOOR MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect mode door motor connector.
3. Reconnect air mix door motor connector (driver side, passenger side).
4. Turn ignition switch ON.
5. Confirm the air mix door motor operation.
OK or NG
OK >> (Air mix door motor operates normally.)

GO TO 9.
NG >> (Air mix door motor does not operate normally.)

GO TO 10.
9. CHECK INTAKE DOOR MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect air mix door motor connector (driver side, passenger side).
3. Reconnect intake door motor connector.
4. Turn ignition switch ON.
5. Confirm the intake door motor operation.
OK or NG
OK >> (Intake door motor operates normally.)

Repair unified meter and A/C amp.
NG >> (Intake door motor does not operate normally.)

Repair intake door motor.

TROUBLE DIAGNOSIS
ATC-69
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AT C
Revision: 2004 November 2004 FX35/FX45
10. CHECK AIR MIX DOOR MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (driver side) connector.
3. Turn ignition switch ON.
4. Confirm the air mix door motor (passenger side) operation.
OK or NG
OK >> (Air mix door motor operates normally.)

Repair driver side air mix door motor.
NG >> (Air mix door motor does not operate normally.)

Repair passenger side air mix door motor.

ATC-70
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
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".
*4AT C - 5 4 , "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6.*5ATC-104, "
Ambient Sensor Circuit".*6ATC-107, "In-vehicle Sensor Cir-
cuit".
*7AT C - 11 0 , "
Sunload Sensor Circuit".*8ATC-73, "Air Mix Door Motor Cir-
cuit".*9ATC-54, "
FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*10AT C - 6 6 , "
DIAGNOSTIC PROCE-
DURE FOR LAN CIRCUIT".*11ATC-130, "
MODE DOOR MOTOR".*12ATC-42, "SYMPTOM TABLE".
RJIA1991E

TROUBLE DIAGNOSIS
ATC-71
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AT C
Revision: 2004 November 2004 FX35/FX45
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 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.
RJIA1777E