Nissan Murano. Manual - part 849

HAC-170

< DTC/CIRCUIT DIAGNOSIS >

[WITH 7 INCH DISPLAY]

U1000 CAN COMM CIRCUIT

DTC/CIRCUIT DIAGNOSIS

U1000 CAN COMM CIRCUIT

Description

INFOID:0000000009722156

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-17, "How to Use CAN Communication Signal Chart"

.

DTC Logic

INFOID:0000000009722157

DTC DETECTION LOGIC

Diagnosis Procedure

INFOID:0000000009722158

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-18, "Trouble Diagno-

sis Flow Chart"

.

NO

>> Perform the intermittent malfunction diagnosis. Refer to 

GI-44, "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

U1010 CONTROL UNIT (CAN)

HAC-171

< DTC/CIRCUIT DIAGNOSIS >

[WITH 7 INCH DISPLAY]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

U1010 CONTROL UNIT (CAN)

Description

INFOID:0000000009722159

Initial diagnosis of A/C auto amp.

DTC Logic

INFOID:0000000009722160

DTC DETECTION LOGIC

Diagnosis Procedure

INFOID:0000000009722161

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.

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.

HAC-172

< DTC/CIRCUIT DIAGNOSIS >

[WITH 7 INCH DISPLAY]

B257B, B257C AMBIENT SENSOR

B257B, B257C AMBIENT SENSOR

Description

INFOID:0000000009722162

COMPONENT DESCRIPTION

Ambient Sensor

• The ambient sensor (1) is installed to the front bumper (left back). 
• 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:0000000009722163

DTC DETECTION LOGIC

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

HAC-

170, "DTC Logic"

 or 

HAC-171, "DTC Logic"

. 

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

−

44

°

C (

−

47

°

F)] and

adjusts the temperature control warmer. 

DTC CONFIRMATION PROCEDURE

1.

CHECK WITH SELF-DIAGNOSIS FUNCTION OF CONSULT

JSIIA1532JP

JPIIA0612GB

DTC

Items

 (CONSULT screen terms)

Diagnostic item is detected when...

Possible cause

B257B

AMBIENT SENSOR

Detected temperature at ambient sensor 

−

44

°

C (

−

47

°

F) or less

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

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

B257C

Detected temperature at ambient sensor 
100

°

C (212

°

F) or more

B257B, B257C AMBIENT SENSOR

HAC-173

< DTC/CIRCUIT DIAGNOSIS >

[WITH 7 INCH DISPLAY]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

1.

Using CONSULT, perform “SELF-DIAGNOSIS RESULTS” of HVAC. 

2.

Check if any DTC No. is displayed in the self-diagnosis results. 

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

HAC-

170, "DTC Logic"

 or 

HAC-171, "DTC Logic"

. 

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

−

44

°

C (

−

47

°

F)] and

adjusts the temperature control warmer. 

Is DTC No.“B257B” or “B257C” displayed?

YES

>> Perform trouble diagnosis for the ambient sensor. Refer to 

HAC-173, "Diagnosis Procedure"

. 

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000009722164

1.

CHECK VOLTAGE BETWEEN AMBIENT SENSOR AND GROUND

1.

Disconnect ambient sensor connector.

2.

Turn ignition switch ON.

3.

Check voltage between ambient sensor harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> GO TO 4.

2.

CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND A/C AUTO AMP. 

1.

Turn ignition switch OFF.

2.

Disconnect A/C auto amp. connector.

3.

Check continuity between ambient sensor harness connector and A/C auto amp. harness connector.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair harness or connector.

3.

CHECK AMBIENT SENSOR

Check ambient sensor. Refer to 

HAC-174, "Component Inspection"

.

Is the inspection result normal?

YES

>> Replace A/C auto amp.

NO

>> Replace ambient sensor.

4.

CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND A/C AUTO AMP.

1.

Turn ignition switch OFF.

2.

Disconnect A/C auto amp. connector.

3.

Check continuity between ambient sensor harness connector and A/C auto amp. harness connector.

4.

Check continuity between ambient sensor harness connector and ground.

(+)

(

−

)

Voltage

Ambient sensor

—

Connector

Terminal

E337

1

Ground

Approx. 5 V

Ambient sensor

A/C auto amp.

Continuity

Connector

Terminal

Connector

Terminal

E337

2

M50

37

Existed

Ambient sensor

A/C auto amp.

Continuity

Connector

Terminal

Connector

Terminal

E337

1

M50

35

Existed