INFINITI M35 2007 Factory Service Manual

ATC-30
AIR CONDITIONER CONTROL
Revision: 2007 April2007 M35/M45
OPERATION
The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp.
sends mode door, air mix door, upper ventilator door and intake door opening angle data to the mode door
motor LCU, air mix door motor LCU, upper ventilator door motor LCU and intake door motor LCU.
The mode door motor, air mix door motors, upper ventilator 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 is compared by the LCUs in each door motor with
the existing decision and opening angles. Subsequently, HOT/COLD, DEF/VENT, OPEN/SHUT and FRE/REC
operation is selected. The new selection data is returned to the unified meter and A/C amp.
TRANSMISSION DATA AND TRANSMISSION ORDER
Unified meter and A/C amp. data is transmitted consecutively to each of the door motors following the form
shown in figure below.
Start:
Initial compulsory signal is sent to each of the door motors.
Address:
Data sent from the unified meter and A/C amp. are selected according to data-based decisions made by the
mode door motor, air mix door motor, upper ventilator door motor and intake door motor.
If the addresses are identical, the opening angle data and error check signals are received by the door motor
LCUs. The LCUs then make the appropriate error decision. If the opening angle data have no error, door con-
trol begins.
If an error exists, the received data are rejected and corrected data received. Finally, door control is based
upon the corrected opening angle data.
Opening angle:
Data that shows the indicated door opening angle of each door motor.
Error Check:
In this procedure, transmitted and received data is checked for errors. Error data are then compiled. The error
check prevents corrupted data from being used by the mode door motor, the air mix door motor, the upper
ventilator door motor and the intake door motor. Error data can be related to the following symptoms.

Malfunction of electrical frequency

Poor electrical connections

Signal leakage from transmission lines

Signal level fluctuation
RJIA4018E

AIR CONDITIONER CONTROL
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Revision: 2007 April2007 M35/M45
Stop signal:
At the end of each transmission, a stop operation, in-operation, or internal malfunction message is delivered to
the unified meter and A/C amp. This completes one data transmission and control cycle.
AIR MIX DOOR CONTROL (AUTOMATIC TEMPERATURE CONTROL)
The air mix doors are automatically controlled so that in-vehicle temperature is maintained at a predetermined
value by the temperature setting, ambient temperature, in-vehicle temperature and amount of sunload.
FAN SPEED CONTROL
Blower speed is automatically controlled by the temperature setting, ambient temperature, in-vehicle tempera-
ture, intake temperature, amount of sunload and air mix door position.
With pressing AUTO switch, the blower motor starts to gradually increase air flow volume.
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flow-
ing.
INTAKE DOOR CONTROL
The intake doors are automatically controlled by the temperature setting, ambient temperature, in-vehicle tem-
perature, intake temperature, amount of sunload and ON/OFF operation of the compressor.
MODE DOOR CONTROL
The mode doors are automatically controlled by the temperature setting, ambient temperature, in-vehicle tem-
perature, intake temperature and amount of sunload.
UPPER VENTILATOR DOOR CONTROL
The upper ventilator door is automatically controlled by the mode setting, and amount of sunload.
RJIA4019E

ATC-32
AIR CONDITIONER CONTROL
Revision: 2007 April2007 M35/M45
MAGNET CLUTCH CONTROL
When A/C switch, AUTO switch or DEF switch is pressed, unified meter and A/C amp. transmits compressor
ON signal to ECM, via CAN communication.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant-pressure sen-
sor signal, throttle angle, etc.). If it judges compressor can be turned ON, it sends compressor ON signal to
IPDM E/R, via CAN communication.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate com-
pressor.
When sending compressor ON signal to IPDM E/R via CAN communication line, ECM simultaneously sends
compressor feedback signal to ECM via CAN communication line.
ECM sends compressor feedback signal to unified meter and A/C amp., then, uses input compressor feed-
back signal to control air inlet.
SELF-DIAGNOSIS SYSTEM
The self-diagnosis system is built into the unified meter and A/C amp. to quickly locate the cause of malfunc-
tions.
RJIA4020E

AIR CONDITIONER CONTROL
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Description of Control SystemNJS000G6
The control system consists of input sensors, switches, the unified meter and A/C amp. (microcomputer) and
outputs. The relationship of these components is shown in the figure below:
Control OperationNJS000G7
DISPLAY SCREEN
RJIA4021E
RJIA4022E

ATC-34
AIR CONDITIONER CONTROL
Revision: 2007 April2007 M35/M45
MULTIFUNCTION SWITCH
DISPLAY SCREEN
The operation status of the system is displayed on the screen.
MODE SWITCH (DRIVER SIDE)

Controls the air discharge outlets.

When the DUAL switch indicator is not illuminated, the driver side and passenger side outlets are
switched together.

When the DUAL switch indicator is illuminated, only the driver side outlet is switched.
MODE SWITCH (PASSENGER SIDE)
When the MODE switch (passenger side) is pressed, the DUAL switch indicator illuminates, and only the pas-
senger side outlet is switched.
TEMPERATURE CONTROL SWITCH (POTENTIO TEMPERATURE CONTROL) (DRIVER SIDE)
The set temperature is Increased or decreased with this switch.
TEMPERATURE CONTROL SWITCH (POTENTIO TEMPERATURE CONTROL) (PASSENGER
SIDE)

The set temperature is Increased or decreased with this switch.

When the temperature switch is pressed, the DUAL switch indicator will automatically illuminate.
AUTO SWITCH

The compressor, intake doors, air mix doors, mode doors and blower speed are automatically controlled
so that the in-vehicle temperature will reach, and be maintained at the set temperature selected by the
operator.

When pressing AUTO switch, air inlet, air outlet, fan speed, and discharge air temperature are automati-
cally controlled.
DEFROSTER (DEF) SWITCH
Mode doors are set to the defrost position with this switch. Also, intake doors are set to the outside air position,
and compressor turns ON.
UPPER VENT SWITCH

When UPPER VENT switch is ON, UPPER VENT switch indicator turn ON, and upper ventilator door is
automatically controlled.

When DEFROSTER (DEF) switch is ON, upper ventilator door is shut.

When MODE position (driver side) is FOOT or D/F, upper ventilation door is shut.
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AIR CONDITIONER CONTROL
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When UPPER VENT switch is OFF, UPPER VENT switch indicator turn OFF, and upper ventilator door is
shut.
A/C SWITCH
Compressor is ON or OFF with this switch.
(Pressing the A/C switch when the A/C switch is ON will turn OFF the A/C switch and compressor.)
FAN SWITCHES
The blower speed is manually controlled with this switch. Seven speeds are available for manual control (as
shown on the display screen).
OFF SWITCH
Compressor and blower are OFF, the intake doors and the mode doors are automatically controlled.
REAR WINDOW DEFOGGER SWITCH
When illumination is ON, rear window is defogged.
INTAKE SWITCH

When intake switch is ON, FRE LED turns ON, and air inlet is fixed to FRE.

When press intake switch again, REC LED turns ON, and air inlet is fixed to REC.

When intake switch is pressed for approximately 1.5 seconds or longer, FRE and REC LEDs blink twice.
Then, automatic control mode is entered. Inlet status is displayed by LED even during automatic con-
trolled.

When FRE LED is turned ON, shifting mode position to D/F or DEF, or when compressor is turned from
ON to OFF, intake switch is automatically turned OFF (fixed to FRE mode). REC mode can be re-entered
by pressing intake switch again, and then compressor is turned ON. (Except D/F or DEF position)
DUAL SWITCH

When the DUAL switch indicator is illuminated, the driver side and passenger side temperature can each
be set independently.

When the DUAL switch indicator is not illuminated, the driver side outlet and setting temperature is
applied to both sides.
Control Operation (Rear Control Switch)NJS000G8
AUTO SWITCH

When pressing AUTO switch, display for turned on AUTO and fan speed is automatically controlled.

When pressing AUTO switch, air inlet, air outlet, fan speed, and discharge air temperature are automati-
cally controlled.
FAN SWITCH
The blower speed is manually controlled with this switch. Five speeds are available for manual control (as
shown on the display screen).
RJIA4216E

ATC-36
AIR CONDITIONER CONTROL
Revision: 2007 April2007 M35/M45
REAR TEMPERATURE CONTROL SWITCH

Increases or decreases the set temperature.

A temperature for the rear seat with respect to a set temperature for the front seat can be adjusted by
operating switch.

Rear temperature control switch allows to select a temperature every 0.5°C (1°F) in the 18°C (60°F) to
32°C (90°F) range.

When the DUAL switch is ON, temperature for the rear seat changes keeping the temperature difference
between two front seats. [e.g. When lowering the set temperature for the rear seat 1°C (2°F) by operating
rear control switch at a set temperature of 25°C (77°F) for the driver’s seat and 26°C (79°F) for the pas-
senger’s seat, the set temperature for the driver’s seat and passenger’s seat lower 1°C (2°F) and become
24°C (75°F) for the driver’s seat and 25°C (77°F) for the passenger’s seat.]
NOTE:
A set temperature for the rear seat is tied to a set temperature for the passenger’s seat. Therefore, a set
temperature for the rear seat changes in conjunction with a set temperature for the passenger’s seat
(When the set temperature of front seats are independent).
Fail-Safe FunctionNJS000G9

If a communication error exists between the unified meter and A/C amp.,and the AV control unit or NAVI
control unit and multifunction switch for 30 seconds or longer, air conditioner is controlled under the follow-
ing conditions:
Compressor : ON
Air outlet : AUTO
Air inlet : FRE (Fresh)
Blower fan speed : AUTO
Set temperature : Setting before communication error occurs
Display : OFF

AIR CONDITIONER CONTROL
ATC-37
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Revision: 2007 April2007 M35/M45
Discharge Air FlowNJS000GA
RJIA4024E

ATC-38
AIR CONDITIONER CONTROL
Revision: 2007 April2007 M35/M45
System DescriptionNJS000GB
SWITCHES AND THEIR CONTROL FUNCTION
SJIA1730E
SJIA1766E

AIR CONDITIONER CONTROL
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Revision: 2007 April2007 M35/M45
CAN Communication System DescriptionNJS000GC
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only. For details, refer to LAN-50,
"CAN System Specification Chart" .