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ATC-62
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
Power Supply and Ground Circuit for Auto Amp.NJS000E2
SYMPTOM: A/C system does not come on.
INSPECTION FLOW
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 control switch are oper-
ated, data is input to the unified meter and A/C amp. from the 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.
*1 ATC-63, "DIAGNOSIS PROCE-
DURE FOR A/C SYSTEM"
*2 ATC-60, "Operational Check"*3AV-84, "Unable to Operate System
with A/C and AV Switch" (Without
navigation system) or AV-139,
"Unable to Operate System with A/C
and AV Switch" (With navigation
system)
SJIA1582E
SJIA1566E
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ATC-64
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
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, 30 and ground.
OK or NG
OK >> Replace unified meter and A/C amp.
NG >> Repair harness or connector.
LAN System CircuitNJS000E3
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 and ground.
OK or NG
OK >> GO TO 2.
NG >> Replace unified meter and A/C amp. 29, 30 – Ground : Continuity should exist.
RJIA1985E
RJIA1775E
54 – Ground : Battery voltage
RJIA1986E
Page 515 of 4462
TROUBLE DIAGNOSIS ATC-69
C
D E
F
G H
I
K L
M A
B
AT C
Revision: 2006 December 2006 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 door motor with the existing decision and open-
ing angles. Subsequently, HOT/COLD, DEF/VENT and FRE/REC operation is selected. The new selection
data are returned to the unified meter and A/C amp.
SJIA1585E
Page 517 of 4462
TROUBLE DIAGNOSIS ATC-71
C
D E
F
G H
I
K L
M A
B
AT C
Revision: 2006 December 2006 FX35/FX45
Air Mix Door Motor CircuitNJS000E5
SYMPTOM
Discharge air temperature does not change.
Air mix door motor does not operate normally.
INSPECTION FLOW
*1 ATC-53, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6. *2
ATC-103, "
Ambient Sensor Circuit"*3 ATC-106, "In-vehicle Sensor Circuit"
*4ATC-109, "Sunload Sensor Circuit"*5ATC-71, "Air Mix Door Motor Circuit"*6 ATC-53, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*7 ATC-64, "
LAN System Circuit".*8 ATC-60, "Operational Check"*9ATC-41, "SYMPTOM TABLE"
*10ATC-112, "Intake Sensor Circuit"
SJIA1586E
Page 518 of 4462
ATC-72
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 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 motor opening angle data to the air mix door motor LCUs,
mode door motor LCU and intake door motor LCU.
The air mix door motors, 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 FRE/REC operation is selected. The new selection
data are returned to the unified meter and A/C amp.
Air Mix Door Control Specification
RJIA1781E
RJIA1782E
Page 520 of 4462
ATC-74
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
Intake Door Motor CircuitNJS000E7
SYMPTOM
Intake door does not change.
Intake door motor does not operate normally.
INSPECTION FLOW
*1 AT C - 5 3 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 4 to 6. *2
ATC-103, "
Ambient Sensor Circuit"*3 ATC-106, "In-vehicle Sensor Circuit"
*4 ATC-109, "Sunload Sensor Circuit"*5AT C - 7 1 , "Air Mix Door Motor Circuit"*6 AT C - 5 3 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*7 AT C - 6 4 , "
LAN System Circuit"*8ATC-123, "INTAKE DOOR MOTOR"*9 AT C - 6 0 , "Operational Check"
*10 AT C - 4 1 , "SYMPTOM TABLE"*11AT C - 11 2 , "Intake Sensor Circuit"
SJIA1587E
Page 521 of 4462
TROUBLE DIAGNOSIS ATC-75
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D E
F
G H
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K L
M A
B
AT C
Revision: 2006 December 2006 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 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 FRESH position.
Intake Door Control Specification
SJIA1588E
RJIA1787E
Page 524 of 4462
ATC-78
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 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 the
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.
RJIA1995E
