Infiniti QX56 (Z62). Manual - part 795

SYSTEM SETTING

HAC-71

< BASIC INSPECTION >

[AUTOMATIC AIR CONDITIONING]

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Movement Change Function

INFOID:0000000006275902

DESCRIPTION

Condition for interlocking movement of auto intake switch and A/C switch can be changed. In addition opera-
tion of the auto intake switch, which activates the automatic intake control (exhaust gas / outside odor detect-
ing mechanism), can be set to become available when the A/C switch is ON.

HOW TO SET

With CONSULT-III

Perform the “CLEAN SW SET” of HVAC work support item. 

NOTE:
When the battery cable is disconnected from the negative terminal or when the battery voltage becomes 10 V
or less, the setting of WORK SUPPORT may be cancelled.

Work support items

Display

Setting

CLEAN SW SET

Mode1

Initial setting

Mode2

Setting 1

Mode3

Setting 2

Mode4

Setting 3

Initial setting

When the auto intake switch is ON, the A/C switch is also turned ON in synchronization with the auto intake 
switch. 
Control of the auto intake switch is functional even when the A/C switch is turned OFF. 

Setting 1

When the auto intake switch is ON, the A/C switch is not turned ON in synchronization with the auto intake 
switch. 
Control of the auto intake switch is functional even when the A/C switch is turned OFF. 

Setting 2

When the auto intake switch is ON, the A/C switch is also turned ON in synchronization with the auto intake 
switch. 
When the A/C switch is turned OFF, the auto intake switch is turned OFF in synchronization with the A/C 
switch. 

Setting 3

Auto intake switch can be turned ON only when A/C switch is ON. 
When the A/C switch is turned OFF, the auto intake switch is turned OFF in synchronization with the A/C 
switch.

HAC-72

< DTC/CIRCUIT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONING]

U1000 CAN COMM CIRCUIT

DTC/CIRCUIT DIAGNOSIS

U1000 CAN COMM CIRCUIT

Description

INFOID:0000000006275903

CAN (Controller Area Network) is a serial communication system for real time application. It is an on-vehicle
multiplex communication system with high data communication speed and excellent error detection ability.
Many electronic control units are equipped onto vehicles, and each control unit shares information and links
with other control units during operation (not independent). In CAN communication, control units are con-
nected with two 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.
CAN Communication Signal Chart. Refer to 

LAN-28, "CAN COMMUNICATION SYSTEM : CAN Communica-

tion Signal Chart"

.

DTC Logic

INFOID:0000000006275904

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PERFORM SELF-DIAGNOSIS

With CONSULT-III

1.

Turn ignition switch ON and wait for 2 seconds or more. 

2.

Select “Self Diagnostic Result” mode of “HVAC” using CONSULT-.III 

3.

Check DTC.

Is DTC detected?

YES

>> Refer to 

HAC-72, "Diagnosis Procedure"

. 

NO

>> Refer to 

GI-40, "Intermittent Incident"

.

Diagnosis Procedure

INFOID:0000000006275905

1.

CHECK CAN COMMUNICATION SYSTEM

Check CAN communication system. Refer to 

LAN-18, "Trouble Diagnosis Flow Chart"

.

>> INSPECTION END

DTC

Items

 (CONSULT-III screen terms)

DTC detection condition

Possible cause

U1000

CAN COMM CIRCUIT

When A/C auto amp. is not transmitting 
or receiving CAN communication signal 
for 2 or more seconds.

CAN communication system

U1010 CONTROL UNIT (CAN)

HAC-73

< DTC/CIRCUIT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONING]

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U1010 CONTROL UNIT (CAN)

Description

INFOID:0000000006275906

Initial diagnosis of A/C auto amp.

DTC Logic

INFOID:0000000006275907

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PERFORM SELF-DIAGNOSIS

With CONSULT-III

1.

Turn ignition switch ON. 

2.

Select “Self Diagnostic Result” mode of “HVAC” using CONSULT-.III 

3.

Check DTC.

Is DTC detected?

YES

>> Refer to 

HAC-73, "Diagnosis Procedure"

.

NO

>> INSPECTION END 

Diagnosis Procedure

INFOID:0000000006275908

1.

REPLACE A/C AUTO AMP.

Replace A/C auto amp.. Refer to 

HAC-146, "Removal and Installation"

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>> INSPECTION END

DTC

Items

 (CONSULT-III screen terms)

DTC detection condition

Possible cause

U1010

CONTROL UNIT (CAN)

When detecting error during the initial diag-
nosis of CAN controller of A/C auto amp.

A/C auto amp.

HAC-74

< DTC/CIRCUIT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONING]

B2578, B2579 FRONT IN-VEHICLE SENSOR

B2578, B2579 FRONT IN-VEHICLE SENSOR

DTC Logic

INFOID:0000000006275909

DTC DETECTION LOGIC 

NOTE:
• If DTC is displayed along with DTC U1000, first perform the trouble diagnosis for DTC U1000. Refer to 

HAC-

72, "DTC Logic"

.

• If DTC is displayed along with DTC U1010, first perform the trouble diagnosis for DTC U1010. Refer to 

HAC-

73, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT-III

1.

Turn ignition switch ON.

2.

Select “Self Diagnostic Result” mode of “HVAC” using CONSULT-III.

3.

Check DTC.

Is DTC detected?

YES

>> Refer to 

HAC-106, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006275910

1.

CHECK FRONT IN-VEHICLE SENSOR POWER SUPPLY

1.

Turn ignition switch OFF.

2.

Disconnect front in-vehicle sensor connector.

3.

Turn ignition switch ON.

4.

Check voltage between front in-vehicle sensor harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> GO TO 4.

2.

CHECK FRONT IN-VEHCLE SENSOR GROUND CIRCUIT 

1.

Turn ignition switch OFF.

2.

Disconnect A/C auto amp. connector.

3.

Check continuity between front in-vehicle sensor harness connector and A/C auto amp. harness connec-
tor.

Is the inspection result normal?

DTC

Items

(CONSULT-III screen terms)

DTC detection condition

Possible cause

B2578

IN-VEHICLE SENSOR

The front in-vehicle sensor recognition temper-
ature is too high.

• Front in-vehicle sensor
• A/C auto amp.
• Harness or connectors

(The sensor circuit is open or short-
ed.)

B2579

The front in-vehicle sensor recognition temper-
ature is too low.

+

−

Voltage

(Approx.)

Front in-vehicle sensor

Connector

Terminal

M73

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Ground

5 V

Front in-vehicle sensor

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Continuity

Connector

Terminal

M73

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Ground

Existed