Nissan Leaf. Manual - part 771

U1000 CAN COMM CIRCUIT

HAC-87

< DTC/CIRCUIT DIAGNOSIS >

[AUTO A/C (WITH HEAT PUMP)]

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DTC/CIRCUIT DIAGNOSIS

U1000 CAN COMM CIRCUIT

Description

INFOID:0000000010121792

CAN (Controller Area Network) is a serial communication line for real time applications. It is an on-board mul-

tiplex communication line with high data communication speed and excellent error detection ability. A modern

vehicle is equipped with many ECMs, and each control unit shares information and links with other control

units during operation (not independent). In CAN communication, 2 control units are connected with 2 commu-

nication lines (CAN-L line and CAN-H line) allowing a high rate of information transmission with less wiring.

Each control unit transmits/receives data but selectively reads required data only. 

Refer to 

LAN-37, "CAN COMMUNICATION SYSTEM : CAN Communication Signal Chart"

 for details of the

communication signal. 

DTC Logic

INFOID:0000000010121793

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Turn power switch ON and wait at least 2 seconds or more.

2. Select “Self Diagnostic Result” of “HVAC” using CONSULT.

3. Check DTC.
Is DTC detected?

YES

>> Refer to 

HAC-87, "Diagnosis Procedure"

.

NO

>> Check intermittent incident. Refer to 

GI-53, "Intermittent Incident"

.

Diagnosis Procedure

INFOID:0000000010121794

1.

CHECK CAN COMMUNICATION SYSTEM

Check CAN communication system. Refer to 

LAN-17, "Trouble Diagnosis Flow Chart"

.

>> Inspection End.

DTC

Items

(CONSULT 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

HAC-88

< DTC/CIRCUIT DIAGNOSIS >

[AUTO A/C (WITH HEAT PUMP)]

U1010 CONTROL UNIT (CAN)

U1010 CONTROL UNIT (CAN)

Description

INFOID:0000000010121795

Initial diagnosis of A/C auto amp.

DTC Logic

INFOID:0000000010121796

DTC DETECTION LOGIC 

DTC CONFIRMATION PROCEDURE

1.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Turn power switch ON.

2. Select “Self Diagnostic Result” of “HVAC” using CONSULT.

3. Check DTC.
Is DTC detected?

YES

>> Refer to 

HAC-88, "Diagnosis Procedure"

.

NO

>> Inspection End.

Diagnosis Procedure

INFOID:0000000010121797

1.

REPLACE A/C AUTO AMP.

Replace A/C auto amp. Refer to 

HAC-187, "Removal and Installation"

.

>> Inspection End.

DTC

Items

(CONSULT screen terms)

DTC detection condition

Possible cause

U1010

CONTROL UNIT (CAN)

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

A/C auto amp.

B2578, B2579 IN-VEHICLE SENSOR

HAC-89

< DTC/CIRCUIT DIAGNOSIS >

[AUTO A/C (WITH HEAT PUMP)]

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B2578, B2579 IN-VEHICLE SENSOR

DTC Logic

INFOID:0000000010121798

DTC DETECTION LOGIC 

NOTE:

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

HAC-

87, "DTC Logic"

.

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

HAC-88,

"DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Turn power switch ON.

2. Select “Self Diagnostic Result” of “HVAC” using CONSULT.

3. Check DTC.
Is DTC detected?

YES

>> Refer to 

HAC-89, "Diagnosis Procedure"

.

NO

>> Inspection End.

Diagnosis Procedure

INFOID:0000000010121799

Regarding Wiring Diagram information, refer to 

HAC-61, "Wiring Diagram"

.

1.

CHECK IN-VEHICLE SENSOR VOLTAGE SIGNAL

1. Turn power switch ON.

2. Operate the automatic air conditioning system.

3. Check voltage signal between A/C auto amp. harness connector terminals.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> GO TO 2.

2.

CHECK IN-VEHICLE SENSOR POWER SUPPLY

DTC

Items

(CONSULT screen terms)

DTC detection condition

Possible cause

B2578

IN-VEHICLE SENSOR

The in-vehicle sensor recognition temperature 
is too high [more than 100

°C (212°F)].

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

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

B2579

The in-vehicle sensor recognition temperature 
is too low [less than 

−42°C (−44°F)].

A/C auto amp.

Test condition

Voltage signal

Connector

+

−

Terminal

M55

33

10

• Power switch ON
• When air conditioner is op-

erating

JSIIA1662ZZ

HAC-90

< DTC/CIRCUIT DIAGNOSIS >

[AUTO A/C (WITH HEAT PUMP)]

B2578, B2579 IN-VEHICLE SENSOR

1. Turn power switch OFF.

2. Disconnect in-vehicle sensor connector. 

3. Turn power switch ON.

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

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 5.

3.

CHECK IN-VEHICLE SENSOR GROUND CIRCUIT FOR OPEN

1. Turn power switch OFF.

2. Disconnect A/C auto amp. connector. 

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

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair harness or connector.

4.

CHECK IN-VEHICLE SENSOR

Check in-vehicle sensor. Refer to 

HAC-91, "Component Inspection"

.

Is the inspection result normal?

YES

>> Replace A/C auto amp. Refer to 

HAC-187, "Removal and Installation"

.

NO

>> Replace in-vehicle sensor. Refer to 

HAC-190, "Removal and Installation"

.

5.

CHECK IN-VEHICLE SENSOR POWER SUPPLY CIRCUIT FOR OPEN

1. Turn power switch OFF.

2. Disconnect A/C auto amp. connector. 

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

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Repair harness or connector.

6.

CHECK IN-VEHICLE SENSOR POWER SUPPLY CIRCUIT FOR SHORT

Check continuity between in-vehicle sensor harness connector and ground. 

Is the inspection result normal?

YES

>> Replace A/C auto amp. Refer to 

HAC-187, "Removal and Installation"

.

NO

>> Repair harness or connector.

+

−

Voltage

(Approx.)

In-vehicle sensor

Connector

Terminal

M42

1

Ground

5 V

In-vehicle sensor

A/C auto amp.

Continuity

Connector

Terminal

Connector

Terminal

M42

2

M55

30

Yes

In-vehicle sensor

A/C auto amp.

Continuity

Connector

Terminal

Connector

Terminal

M42

1

M55

33

Yes

In-vehicle sensor

—

Continuity

Connector

Terminal

M42

1

Ground

No