Nissan Maxima. Manual - part 739

HAC-132

< SYSTEM DESCRIPTION >

[WITH MONOCHROME DISPLAY]

DIAGNOSIS SYSTEM (HVAC)

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

U1000 CAN COMM CIRCUIT

HAC-133

< DTC/CIRCUIT DIAGNOSIS >

[WITH MONOCHROME DISPLAY]

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DTC/CIRCUIT DIAGNOSIS

U1000 CAN COMM CIRCUIT

Description

INFOID:0000000010051127

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 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-14, "How to Use CAN Communication Signal Chart"

.

DTC Logic

INFOID:0000000010051128

DTC DETECTION LOGIC

Diagnosis Procedure

INFOID:0000000010051129

1.

CHECK WITH SELF-DIAGNOSIS FUNCTION OF CONSULT

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

2. Using CONSULT, perform “SELF-DIAGNOSIS RESULTS” of HVAC. 
Is “CAN COMM CIRCUIT” displayed?

YES

>> Perform trouble diagnosis for the CAN communication system. Refer to 

LAN-15, "Trouble Diagno-

sis Flow Chart"

.

NO

>> Perform the intermittent malfunction diagnosis. Refer to 

GI-41, "Intermittent Incident"

.

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

HAC-134

< DTC/CIRCUIT DIAGNOSIS >

[WITH MONOCHROME DISPLAY]

U1010 CONTROL UNIT (CAN)

U1010 CONTROL UNIT (CAN)

Description

INFOID:0000000010051130

Initial diagnosis of A/C auto amp.

DTC Logic

INFOID:0000000010051131

DTC DETECTION LOGIC

Diagnosis Procedure

INFOID:0000000010051132

1.

CHECK WITH SELF-DIAGNOSIS FUNCTION OF CONSULT

Using CONSULT, perform “SELF-DIAGNOSIS RESULTS” of HVAC. 
Is DTC No.“U1010” displayed?

YES

>> Replace A/C auto amp. Refer to 

HAC-203, "Removal and Installation"

.

NO

>> Inspection End.

DTC

Items

 (CONSULT screen terms)

Diagnostic item is detected when...

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.

B257B, B257C AMBIENT SENSOR

HAC-135

< DTC/CIRCUIT DIAGNOSIS >

[WITH MONOCHROME DISPLAY]

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B257B, B257C AMBIENT SENSOR

Description

INFOID:0000000010051133

COMPONENT DESCRIPTION

Ambient Sensor

• The ambient sensor (1) is installed to the front bumper reinforce-

ment. 

• It detects ambient temperature and converts it into a resistance

value which is then input into the A/C auto amp.

Ambient Sensor Circuit

AMBIENT TEMPERATURE INPUT PROCESS

The A/C auto amp. equips a processing circuit for the ambient sensor input. However, when the temperature

detected by the ambient sensor increases quickly, the processing circuit retards the A/C auto amp. function. It

only allows the A/C auto amp. to recognize an ambient temperature increase of 0.33

°C (0.6°F) per 100 sec-

onds.

As an example, consider stopping for a few minutes after high speed driving. Although the actual ambient tem-

perature has not changed, the temperature detected by the ambient sensor increases. This is because the

heat from the engine compartment can radiate to the front bumper area, the location of the ambient sensor.

DTC Logic

INFOID:0000000010051134

DTC DETECTION LOGIC

NOTE:

• If DTC is displayed along with DTC U1000 or U1010, first diagnose the DTC U1000 or U1010. Refer to 

HAC-

133, "DTC Logic"

 or 

HAC-134, "DTC Logic"

. 

• If there is an open circuit in the ambient sensor, A/C auto amp. registers extreme cold [-30

°C (-22°F)] and

adjusts the temperature control warmer. 

DTC CONFIRMATION PROCEDURE

1.

CHECK WITH SELF-DIAGNOSIS FUNCTION OF CONSULT

ALIIA0314ZZ

JPIIA0612GB

DTC

Items

 (CONSULT screen terms)

Diagnostic item is detected when...

Possible cause

B257B

AMB TEMP SEN (SHORT)

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