Nissan Altima L32. Manual - part 812

HAC-22

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

SELF-DIAGNOSIS FUNCTION

SELF-DIAGNOSIS FUNCTION

Diagnosis Description

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SELF-DIAGNOSIS SYSTEM

The self-diagnosis system is built into the front air control to quickly locate the cause of malfunctions.

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 (pressing the ignition switch to the ON position) and pressing OFF switch for at least 5 sec-

onds. The OFF switch must be pressed within 10 seconds after starting the engine (ignition switch is pressed

to the ON position). This system will be canceled by either pressing AUTO switch or pressing the ignition

switch OFF. Shifting from one step is accomplished by means of turning temperature control dial (LH side), as

required.

SELF-DIAGNOSIS FUNCTION

HAC-23

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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Shifting from STEP-5 to AUXILIARY MECHANISM is accomplished by turning the LH temperature control dial

clockwise or counterclockwise.

CONFIRMATION METHOD

1.

SET IN SELF-DIAGNOSIS MODE

1. Press ignition switch ON.

2. Set in self-diagnosis mode as follows. Within 10 seconds after starting engine (ignition switch is pressed

ON.), press OFF switch for at least 5 seconds.

NOTE:

AWIIA0609GB

HAC-24

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

SELF-DIAGNOSIS FUNCTION

• 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. To avoid this, start engine before

performing this diagnosis.

• Former STEP-1 (LEDs and display screen are checked) does not exist in this self-diagnosis function.

>> GO TO 2

2.

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

Does code No. 20 appear on the display?

YES

>> GO TO 3

NO

>> GO TO 12

3.

CHECK TO ADVANCE SELF-DIAGNOSIS STEP-3

Turn temperature control dial (LH) clockwise.
Advance to self-diagnosis STEP-3?

YES

>> GO TO 4

NO

>> Replace front air control. (Temperature control dial is malfunctioning.) Refer to 

VTL-8, "Removal

and Installation"

.

4.

CHECK TO RETURN SELF-DIAGNOSIS STEP-2

Turn temperature control dial (LH) counterclockwise.
Return to self-diagnosis STEP-2?

YES

>> GO TO 5

NO

>> Malfunctioning front air control. Refer to 

VTL-8, "Removal and Installation"

.

5.

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

Turn temperature control dial (LH) clockwise.
Does code No. 30 appear on the display?

YES

>> GO TO 6

NO

>> GO TO 13

6.

STEP-4: OPERATION OF EACH DOOR MOTOR IS CHECKED

1. Turn temperature control dial (LH side) clockwise.
2. Press 

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

indicated on the display.

>> GO TO 7

SJIA1778E

SJIA1779E

SJIA1780E

SELF-DIAGNOSIS FUNCTION

HAC-25

< FUNCTION DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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7.

CHECK ACTUATORS

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

pressor operation.

Checks must be made visually, by listening to the sound, or by touching air outlets with hand, etc. for improper

operation.

*1: FOOT position during automatic control. Refer to 

HAC-5, "Description and Conditions"

.

Is the inspection result normal?

YES

>> GO TO 8

NO

>> • Air outlet does not change.

Go to Mode Door Motor Circuit. Refer to 

HAC-32, "Diagnosis Procedure"

.

• Discharge air temperature does not change.

Go to Air Mix Door Motor Circuit. Refer to 

HAC-35, "Diagnosis Procedure"

.

• Intake door does not change.

Go to Intake Door Motor Circuit. Refer to 

HAC-38, "Diagnosis Procedure"

.

• Blower motor operation is malfunctioning.

Go to Blower Motor Circuit. Refer to 

HAC-42, "Diagnosis Procedure"

.

• Magnet clutch does not engage.

Go to Magnet Clutch Circuit. Refer to 

HAC-47, "Diagnosis Procedure"

.

8.

STEP-5: TEMPERATURE OF EACH SENSOR IS CHECKED

1. Turn temperature control dial (LH) clockwise.

2. Code No. 51 appears on the display.

>> GO TO 9

9.

CHECK AMBIENT SENSOR

Press 

 (DEF) switch one time. Temperature detected by ambient

sensor is indicated on the display.

NOTE:

If the temperature indicated on the display greatly differs from the

actual temperature, check sensor circuit first, and then check sensor.
Is the inspection result normal?

YES

>> GO TO 10

NO

>> Go to Ambient Sensor Circuit. Refer to 

HAC-50, "Diag-

nosis Procedure"

.

Mode door position

Air outlet/distribution

Vent

Foot

Defroster

100%

—

—

44%

56%

—

17%

59%

24%

16%

52%

32%

12%

—

88%

Code  No.

41

42

43

44

45

46

Mode door position

VENT

B/L 1

B/L 2

FOOT

*1

D/F

DEF

Intake door position

REC

REC

20% FRE

FRE

FRE

FRE

Air mix door position

FULL COOL

FULL COOL

FULL HOT

FULL HOT

FULL HOT

FULL HOT

Blower motor duty ratio

37%

91%

65%

65%

65%

91%

Compressor

ON

ON

OFF

OFF

ON

ON

PJIA0151E