Infiniti G37 Coupe. Manual - part 763

CAN COMMUNICATION SYSTEM

HAC-41

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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CAN COMMUNICATION SYSTEM

System Description

INFOID:0000000001675681

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-25,

"CAN System Specification Chart"

.

HAC-42

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

DIAGNOSIS SYSTEM (AUTO AMP.)

DIAGNOSIS SYSTEM (AUTO AMP.)

WITHOUT LEFT AND RIGHT VENTILATION TEMPERATURE SEPARATELY
CONTROL SYSTEM

WITHOUT LEFT AND RIGHT VENTILATION TEMPERATURE SEPARATELY CON-
TROL SYSTEM : Diagnosis Description

INFOID:0000000001675682

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.

SELF-DIAGNOSIS FUNCTION

The self-diagnosis system diagnoses sensors, door motors, blower motor, etc. by system line. Refer to appli-
cable sections (items) for details. Shifting from normal control to the self-diagnosis system is accomplished by
starting the engine (turning the ignition switch ON) and pressing OFF switch for at least 5 seconds. The OFF
switch must be pressed within 10 seconds after starting the engine (ignition switch is turned ON). This system
is canceled by either pressing AUTO switch or turning the ignition switch OFF. Shifting from one step is
accomplished by means of turning temperature control dial, as required.

DIAGNOSIS SYSTEM (AUTO AMP.)

HAC-43

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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HAC

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Shifting from STEP-5 to AUXILIARY MECHANISM is accomplished by means of turning fan control dial clock-
wise.

CONFORMATION METHOD

1.

SET IN SELF-DIAGNOSIS MODE

1.

Turn ignition switch ON.

2.

Set in self-diagnosis mode as per the following. Press OFF switch for at least 5 seconds within 10 sec-
onds after starting engine (ignition switch is turned ON).

NOTE:
• If battery voltage drops below 12 V during diagnosis STEP-3, door motor speed becomes slower and as a

result, the system may generate an error even when operation is normal. Start engine before performing this
diagnosis to avoid this.

• Former STEP-1 (LEDs and display screen are checked) does not exist in this self-diagnosis function.
• OFF switch may not be recognized according to the timing of pressing it. Operate OFF switch after turning

the intake switch LEDs (REC/FRE) ON.

>> GO TO 2.

2.

STEP-2: SENSOR AND DOOR MOTOR CIRCUITS ARE CHECKED FOR OPEN OR SHORT CIRCUIT

JSIIA0770GB

HAC-44

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

DIAGNOSIS SYSTEM (AUTO AMP.)

Does code No. 20 appear on the display?

YES

>> GO TO 3.

NO

>> GO TO 11.

3.

STEP-3: MODE DOOR AND INTAKE DOOR POSITIONS ARE CHECKED

Turn temperature control dial clockwise.

Does code No. 30 appear on the display?

YES

>> GO TO 4.

NO

>> GO TO 12.

4.

STEP-4: OPERATION OF EACH DOOR MOTOR IS CHECKED

1.

Turn temperature control dial clockwise.

2.

Press DEF (

) switch. Code No. of each door motor test is

indicated on the display.

>> GO TO 5.

5.

CHECK ACTUATORS

Refer to the following chart and check discharge air flow, air temperature, blower motor duty ratio and com-
pressor operation.

SJIA1778E

SJIA1779E

SJIA1780E

JSIIA0242GB