Nissan Altima L32. Instruction — part 811

HAC-18

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

AUTOMATIC AIR CONDITIONER SYSTEM

The front air control receives data from each of the sensors. The front air control sends mode door, air mix

doors and intake door opening angle data to the mode door motor LCU, air mix door motors LCUs and intake

door motor LCU.

The mode door motor, air mix door motors and intake door motor read their respective signals according to the

address signal. Opening angle indication signals received from the front air control and each of the motor posi-

tion sensors is compared by the LCUs in each door motor with the existing decision and opening angles. Sub-

sequently, HOT/COLD, DEF/VENT and FRE/REC operation is selected. The new selection data is returned to

the front air control.

Transmission Data and Transmission Order

Front air control data is transmitted consecutively to each of the doors motor following the form shown in figure

below.

START:

• Initial compulsory signal is sent to each of the door motors.

ADDRESS:

• Data sent from the front air control are selected according to data-based decisions made by the mode door

motor, air mix door motors 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

control 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 motors 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

STOP SIGNAL:

AWIIA0051GB

AUTOMATIC AIR CONDITIONER SYSTEM

HAC-19

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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• At the end of each transmission, a stop operation, in-operation, or internal malfunction message is delivered

to the front air control. 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.

BLOWER 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 door is automatically controlled by the temperature setting, ambient temperature, in-vehicle temper-

ature, intake temperature and amount of sunload.

MAGNET CLUTCH CONTROL

When A/C switch, AUTO switch or DEF switch is pressed, front air control transmits compressor ON signal to

ECM, via CAN communication.

WJIA0882E

AWIIA0011GB

HAC-20

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

AUTOMATIC AIR CONDITIONER SYSTEM

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.

Component Part Location

INFOID:0000000004498195

ENGINE COMPARTMENT

Refer to

HAC-9, "Component Part Location"

.

PASSENGER COMPARTMENT

Refer to

HAC-9, "Component Part Location"

.

Component Description

INFOID:0000000004498196

Refer to

HAC-11, "Component’s Role"

.

DIAGNOSIS SYSTEM (ECM)

HAC-21

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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DIAGNOSIS SYSTEM (ECM)

CONSULT-III Function

INFOID:0000000004498198

CONSULT-III APPLICATION ITEMS

CONSULT-III can display each diagnosis item using the diagnosis test modes shown following.

DATA MONITOR

Display Item List

System part

Check item, diagnosis mode

Description

ECM

Data monitor

Displays ECM input data in real time.

Monitor item name

“operation or unit”

Contents

IGN ON SW

“ON/OFF” Displays “IGN position (ON)/OFF, ACC position (OFF)” status as judged from ignition switch signal.

FAN ON SIG

“ON/OFF” Displays “FAN (ON)/FAN (OFF)” status as judged from blower fan motor switch signal.

AIR COND SW

“ON/OFF”

Displays “COMP (ON)/COMP (OFF)” status as judged from air conditioner switch signal.

REFRIGERANT
PRESSURE SEN-
SOR

“V”

Displays “Refrigerant pressure sensor for voltage” status as inputted from refrigerant pressure sen-
sor.