Nissan Maxima. Manual - part 738

HAC-128

< SYSTEM DESCRIPTION >

[WITH MONOCHROME DISPLAY]

CAN COMMUNICATION SYSTEM

CAN COMMUNICATION SYSTEM

System Description

INFOID:0000000010051125

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 each 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-24, "CAN System Specification Chart"

.

DIAGNOSIS SYSTEM (HVAC)

HAC-129

< SYSTEM DESCRIPTION >

[WITH MONOCHROME DISPLAY]

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DIAGNOSIS SYSTEM (HVAC)

CONSULT Function

INFOID:0000000010051126

CONSULT can display each diagnosis item using the diagnosis test modes as shown. 

CONSULT application items

SELF-DIAGNOSTIC RESULT

Refer to 

HAC-171, "DTC Index"

.

Display Item List

Diagnosis mode

Description

ECU Identification

Displays the A/C auto amp. number.

Self-Diagnostic Result

Displays the diagnosis results judged by A/C auto amp.

Data Monitor

Displays A/C auto amp. input/output data in real time.

Active Test

The signals used to activate each device are forcibly supplied from A/C auto amp.

CAN diag support monitor

The results of transmit/receive diagnosis of CAN communication can be read.

Work Support

Changes the setting for each system function.

DTC

Items

 (CONSULT screen terms)

Diagnostic item is detected when...

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)

When detecting error during the initial 
diagnosis of CAN controller of A/C auto 
amp.

A/C auto amp.

B257B

AMB TEMP SEN (SHORT)

Detected temperature at ambient sen-
sor 55

°C (131°F) or more

• Ambient sensor
• A/C auto amp.
• Harness and connector

(Ambient sensor circuit is open, 
or there is a short in the circuit)

B257C

AMB TEMP SEN (OPEN)

Detected temperature at ambient sen-
sor 

−30°C (−22°F) or less

B2578

IN-CAR SENSOR (OUT OF RANGE 
[LOW])

Detected temperature at in-vehicle sen-
sor 55

°C (131°F) or more

• In-vehicle sensor
• A/C auto amp.
• Harness and connector

(In-vehicle sensor circuit is open, 
or there is a short in the circuit)

B2579

IN-CAR SENSOR (OUT OF RANGE 
[HI])

Detected temperature at in-vehicle sen-
sor 

−30°C (−22°F) or less

B2581

EVAP TEMP SEN (SHORT)

Detected temperature at intake sensor 
55

°C (131°F) or more

• Intake sensor
• A/C auto amp.
• Harness and connector

(Intake sensor circuit is open, or 
there is a short in the circuit)

B2582

EVAP TEMP SEN (OPEN)

Detected temperature at intake sensor 
−30°C (−22°F) or less

B2630

*

SUNLOAD SEN (SHORT)

Detected calorie at sunload sensor 
1395 w/m

2

 (1200 kcal/m

2

·h) 

• Sunload sensor
• A/C auto amp.
• Harness and connector

(Sunload sensor circuit is open, 
or there is a short in the circuit)

B2631

*

SUNLOAD SEN (OPEN)

Detected calorie at sunload sensor 0 w/
m

2

 (0 kcal/m

2

·h) 

B2632

DR AIRMIX ACTR (SHORT)

Air mix door PBR (driver side) position 
5% or less

• Air mix door motor (driver side)
• A/C auto amp.
• Harness and connector

(CAN communication line is open 
or shorted)
(Air mix door motor is open or 
shorted)

B2633

DR AIRMIX ACTR (OPEN)

Air mix door PBR (driver side) position 
95% or more

HAC-130

< SYSTEM DESCRIPTION >

[WITH MONOCHROME DISPLAY]

DIAGNOSIS SYSTEM (HVAC)

*: Perform self-diagnosis under sunshine. When performing indoors, aim a light (more than 60 W) at sunload sensor, otherwise self-diag-
nosis reports an error even though the sunload sensor is functioning normally.

DATA MONITOR

Display item list

B2634

PASS AIRMIX ACTR (SHORT)

Air mix door PBR (passenger side) po-
sition 5% or less

• Air mix door motor (passenger 

side)

• A/C auto amp.
• Harness and connector

(CAN communication line is open 
or shorted)
(Air mix door motor is open or 
shorted)

B2635

PASS AIRMIX ACTR (OPEN)

Air mix door PBR (passenger side) po-
sition 95% or more

B2636

DR VENT DOOR FAIL

When the malfunctioning door position 
is detected at VENT position

• Mode door motor
• A/C auto amp.
• Harness and connector

(CAN communication line is open 
or shorted)
(Mode door motor is open or 
shorted)

B2637

DR B/L DOOR FAIL

When the malfunctioning door position 
is detected at B/L position

B2638

DR D/F1 DOOR FAIL

When the malfunctioning door position 
is detected at FOOT position

B2639

DR DEF DOOR FAIL

When the malfunctioning door position 
is detected at DEF position

B263D

FRE DOOR FAIL

When the malfunctioning intake door 
position is detected at FRE position

• Intake door motor
• A/C auto amp.
• Harness and connector

(CAN communication line is open 
or shorted)
(Intake door motor is open or 
shorted)

B263E

20P FRE DOOR FAIL

When the malfunctioning intake door 
position is detected at 20%FRE posi-
tion

B263F

REC DOOR FAIL

When the malfunctioning intake door 
position is detected at REC position

B2654

D/F2 DOOR FAIL

When the malfunctioning door position 
is detected at D/F position

• Mode door motor
• A/C auto amp.
• Harness and connector

(CAN communication line is open 
or shorted)
(Mode door motor is open or 
shorted)

B2655

B/L2 DOOR FAIL

When the malfunctioning door position 
is detected at B/L2 position

DTC

Items

 (CONSULT screen terms)

Diagnostic item is detected when...

Possible cause

Monitor item [Unit]

Description

COMP REQ SIG

[On/Off] Displays A/C switch ON/OFF status transmitted to other units via CAN communication

FAN REQ SIG

[On/Off]

Displays blower switch ON/OFF status transmitted to other units via CAN communica-
tion

AMB TEMP SEN

[

°C]

Ambient sensor value converted from ambient sensor signal received from ambient 
sensor 

IN-VEH TEMP

[

°C]

In-vehicle sensor value converted from in-vehicle sensor signal received from in-vehi-
cle sensor 

INT TEMP SEN

[

°C] Intake sensor value converted from intake sensor signal received from intake sensor 

SUNLOAD SEN

[w/m

2

]

Sunload sensor value converted from sunload sensor signal received from sunload 
sensor 

AMB SEN CAL

[

°C] Ambient sensor value calculated by A/C auto amp.

IN-VEH CAL

[

°C] In-vehicle sensor value calculated by A/C auto amp.

INT TEMP CAL

[

°C] Intake sensor value calculated by A/C auto amp.

SUNL SEN CAL

[w/m

2

] Sunload sensor value calculated by A/C auto amp.

FAN DUTY

[%] Duty ratio of blower motor judged by A/C auto amp.

XM

[

°C]

Target discharge air temperature judged by A/C auto amp. according to the tempera-
ture setting and the value from each sensor

DIAGNOSIS SYSTEM (HVAC)

HAC-131

< SYSTEM DESCRIPTION >

[WITH MONOCHROME DISPLAY]

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ACTIVE TEST

HVAC TEST

NOTE:
Perform the inspection of each output device after starting the engine, because the A/C compressor has been operating. 

WORK SUPPORT

NOTE:

ENG COOL TEMP

[

°C] Water temperature signal value received from ECM via CAN communication

VEHICLE SPEED

[mph

(km/h)]

Vehicle speed signal value received from meter via CAN communication

Monitor item [Unit]

Description

Test item

Description

HVAC TEST

The operation check of A/C system can be performed by selecting the mode. Refer to the fol-
lowing table for the conditions of each mode.

Test item

MODE 1

MODE 2

MODE 3

MODE 4

MODE 5

MODE 6

Mode door position

VENT1

B/L1

B/L2

FOOT

D/F

DEF

Intake door position

REC

REC

20%FRE

FRE

FRE

FRE

Air mix door position 
(driver & passenger 
side)

FULL COLD

FULL COLD

FULL HOT

FULL HOT

FULL HOT

FULL HOT

Blower motor duty ratio

37%

91%

65%

65%

65%

91%

A/C compressor (Mag-
net clutch)

ON

ON

OFF

OFF

ON

ON

Work item

Description

Reference

TEMP SET CORRECT
(Setting of difference between tem-
perature setting and control tempera-
ture)

If the temperature felt by the customer is different than the airflow 
temperature controlled by the temperature setting, the auto ampli-
fier control temperature can be adjusted to compensate for the 
temperature setting. 

HAC-109, "Temperature 
Setting Trimmer"

BLOW SET
(Blow setting to DEF in FOOT mode)

In the FOOT mode, the air blowing to the DEF can change ON/
OFF. 

HAC-110, "Foot Position 
Setting Trimmer"

FRE MEMORY SET
(FRE memory function setting)

• If the ignition switch is turned to the OFF position while the FRE 

switch is set to ON (fresh air intake), “Perform the memory” or 
“Do not perform the memory” of the FRE switch ON (fresh air in-
take) condition can be selected. 

• If “Perform the memory” was set, the FRE switch will be ON 

(fresh air intake) when turning the ignition switch to the ON posi-
tion again. 

• If “Do not perform the memory” was set, the air inlets will be con-

trolled automatically when turning the ignition switch to the ON 
position again. 

HAC-110, "Inlet Port 
Memory Function (FRE)"

REC MEMORY SET
(REC memory function setting)

• If the ignition switch is turned to the OFF position while the REC 

switch is set to ON (recirculation), “Perform the memory” or “Do 
not perform the memory” of the REC switch ON (recirculation) 
condition can be selected. 

• If “Perform the memory” was set, the REC switch will be ON (re-

circulation) when turning the ignition switch to the ON position 
again. 

• If “Do not perform the memory” was set, the air inlets will be con-

trolled automatically when turning the ignition switch to the ON 
position again. 

HAC-111, "Inlet Port 
Memory Function (REC)"