Nissan Leaf. Manual - part 279

C1AC8 BRAKE POWER SUPPLY BACKUP UNIT

BR-437

< DTC/CIRCUIT DIAGNOSIS >

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3. Disconnect 12V battery cable from negative terminal. Refer to 

BR-6, "Precaution for Removing 12V Bat-

tery"

.

4. Disconnect the electrically-driven intelligent brake unit harness connector.

5. Disconnect the brake power supply backup unit harness connector.

6. Check the continuity between electrically-driven intelligent brake unit and brake power supply backup unit.

7. Check the continuity between brake power supply backup unit and ground.

Is the inspection result normal?

YES

>> GO TO 17.

NO

>> Repair or replace error-detected parts and GO TO 17.

17.

CHECK BRAKE POWER SUPPLY BACKUP UNIT POWER SUPPLY

1. Connect 12V battery cable to negative terminal.

2. Check the voltage between brake power supply backup unit and ground.

3. Turn the power switch ON without depressing the brake pedal.

CAUTION:

Never set the vehicle to READY.

4. Check the voltage between brake power supply backup unit and ground.

Is the inspection result normal?

YES

>> GO TO 19.

NO

>> GO TO 18.

18.

CHECK BRAKE POWER SUPPLY BACKUP UNIT POWER SUPPLY CIRCUIT

1. Turn the power switch OFF to exit CONSULT, and disconnect CONSULT from data link connector.

2. Close all doors (including back door), check that the room lamp is OFF, get out of the vehicle, and wait for

3 minutes or more with all doors closed.

CAUTION:

Never operate the vehicle while waiting.

3. Check the 15A fuse (#82).

4. Disconnect 12V battery cable from negative terminal. Refer to 

BR-6, "Precaution for Removing 12V Bat-

tery"

.

5. Check the continuity and for short circuit between harness connector terminal 6 of brake power supply

backup unit and 15A fuse (#82).

Is the inspection result normal?

YES

>> GO TO 19.

Electrically-driven intelligent brake unit

Brake power supply backup unit

Continuity

Connector

Terminal

Connector

Terminal

E34

31

B15

1

Existed

4

Not existed

5

Not existed

6

Not existed

Brake power supply backup unit

—

Continuity

Connector

Terminal

B15

1

Ground

Not existed

Brake power supply backup unit

—

Voltage

(Approx.)

Connector

Terminal

B15

6

Ground

9 

− 16 V

Brake power supply backup unit

—

Voltage

(Approx.)

Connector

Terminal

B15

6

Ground

9 

− 16 V

BR-438

< DTC/CIRCUIT DIAGNOSIS >

C1AC8 BRAKE POWER SUPPLY BACKUP UNIT

NO

>> Perform trouble diagnosis for 12V battery power supply. Refer to 

PG-15, "Wiring Diagram — Bat-

tery Power Supply —"

.

19.

CHECK BRAKE POWER SUPPLY BACKUP UNIT COMMUNICATION CIRCUIT

1. Check the continuity between electrically-driven intelligent brake unit and brake power supply backup unit.

2. Check the continuity between brake power supply backup unit and ground.

Is the inspection result normal?

YES

>> GO TO 20.

NO

>> Repair or replace error-detected parts. GO TO 20.

20.

CHECK BRAKE POWER SUPPLY BACKUP UNIT WAKE UP CIRCUIT

1. Check the continuity between electrically-driven intelligent brake unit and brake power supply backup unit.

2. Check the continuity between brake power supply backup unit and ground.

Is the inspection result normal?

YES

>> Replace the brake power supply backup unit. Refer to 

BR-513, "Removal and Installation"

.

NO

>> Repair or replace error-detected parts.

Electrically-driven intelligent brake unit

Brake power supply backup unit

Continuity

Connector

Terminal

Connector

Terminal

E34

37

B15

1

Not existed

4

Not existed

5

Existed

6

Not existed

Brake power supply backup unit

—

Continuity

Connector

Terminal

B15

5

Ground

Not existed

Electrically-driven intelligent brake unit

Brake power supply backup unit

Continuity

Connector

Terminal

Connector

Terminal

E34

22

B15

1

Not existed

4

Existed

5

Not existed

6

Not existed

Brake power supply backup unit

—

Continuity

Connector

Terminal

B15

4

Ground

Not existed

C1AD0 BRAKE POWER SUPPLY BACKUP UNIT

BR-439

< DTC/CIRCUIT DIAGNOSIS >

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C1AD0 BRAKE POWER SUPPLY BACKUP UNIT

DTC Logic

INFOID:0000000010123089

DTC DETECTION LOGIC

DTC REPRODUCTION PROCEDURE

1.

PRECONDITIONING

If “DTC CONFIRMATION PROCEDURE” has been previously conducted, always turn power switch OFF and

wait at least 10 seconds before conducting the next test.

>> GO TO 2.

2.

CHECK DTC DETECTION

With CONSULT

1. Turn the power switch OFF to ON without depressing the brake pedal.

CAUTION:

Never set the vehicle to READY.

2. Repeat step 1 two or more times.

CAUTION:

Be sure to wait for 5 seconds or more after turning the power switch OFF.

3. Turn the power switch OFF to exit CONSULT, and disconnect CONSULT from data link connector.

4. Close all doors (including back door), check that the room lamp is OFF, get out of the vehicle, and wait for

3 minutes or more with all doors closed.

CAUTION:

Never operate the vehicle while waiting.

5. Turn the power switch ON without depressing the brake pedal.

CAUTION:

Never set the vehicle to READY.

6. Start CONSULT and erase self-diagnosis result of “BRAKE”.

7. Turn the power switch OFF to exit CONSULT, and disconnect CONSULT from data link connector.

8. Close all doors (including back door), check that the room lamp is OFF, get out of the vehicle, and wait for

3 minutes or more with all doors closed.

CAUTION:

Never operate the vehicle while waiting.

9. Turn the power switch ON without depressing the brake pedal.

CAUTION:

Never set the vehicle to READY.

10. Depress brake pedal by 100 mm (3.94 in) or more, and hold the position for 5 seconds or more.

11. Release brake pedal.

12. Start CONSULT and perform “BRAKE” self-diagnosis.
Is DTC “C1AD0” detected?

YES

>> Proceed to 

BR-440, "Diagnosis Procedure"

.

NO

>> INSPECTION END

DTC

Display item

Malfunction detection condition

Possible causes

C1AD0

POWER SUPPLY BACKUP UNIT 
VOLT-2

• An internal malfunction (overvoltage) is de-

tected in the brake power supply backup unit.

• Power voltage of brake power supply backup 

unit is as shown below.

- Power voltage of brake power supply backup 

unit: 9 V 

≥ Power voltage of brake power sup-

ply backup unit

- Power voltage of brake power supply backup 

unit: 16 V 

≤ Power voltage of brake power 

supply backup unit

• Harness or connector
• Fuse
• Brake power supply backup 

unit

• Electrically-driven intelligent 

brake unit

• 12V battery is low

BR-440

< DTC/CIRCUIT DIAGNOSIS >

C1AD0 BRAKE POWER SUPPLY BACKUP UNIT

Diagnosis Procedure

INFOID:0000000010123090

1.

CHECK 12V BATTERY

1. Turn the power switch OFF to exit CONSULT, and disconnect CONSULT from data link connector.

2. Close all doors (including back door), check that the room lamp is OFF, get out of the vehicle, and wait for

3 minutes or more with all doors closed.

CAUTION:

Never operate the vehicle while waiting.

3. Check the 12V battery terminal connections. Refer to 

BR-6, "Precaution for Removing 12V Battery"

 and

PG-83, "Work Flow"

.

4. Check the 12V battery. Refer to 

PG-83, "Work Flow"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace error-detected parts and GO TO 2.

2.

PERFORM SELF-DIAGNOSIS (1)

With CONSULT

1. Connect 12V battery cable to negative terminal.

2. Turn the power switch OFF to ON without depressing the brake pedal.

CAUTION:

Never set the vehicle to READY.

3. Repeat step 2 two or more times.

CAUTION:

Be sure to wait for 5 seconds or more after turning the power switch OFF.

4. Turn the power switch OFF to exit CONSULT, and disconnect CONSULT from data link connector.

5. Close all doors (including back door), check that the room lamp is OFF, get out of the vehicle, and wait for

3 minutes or more with all doors closed.

CAUTION:

Never operate the vehicle while waiting.

6. Turn the power switch ON without depressing the brake pedal.

CAUTION:

Never set the vehicle to READY.

7. Start CONSULT and erase self-diagnosis result of “BRAKE”.

8. Turn the power switch OFF to exit CONSULT, and disconnect CONSULT from data link connector.

9. Close all doors (including back door), check that the room lamp is OFF, get out of the vehicle, and wait for

3 minutes or more with all doors closed.

CAUTION:

Never operate the vehicle while waiting.

10. Turn the power switch ON without depressing the brake pedal.

CAUTION:

Never set the vehicle to READY.

11. Depress brake pedal by 100 mm (3.94 in) or more, and hold the position for 5 seconds or more.

12. Release brake pedal.

13. Start CONSULT and perform “BRAKE” self-diagnosis.
Is DTC “C1AD0” detected?

YES

>> GO TO 3.

NO

>> INSPECTION END

3.

CHECK CONNECTOR TERMINALS

1. Turn the power switch OFF to exit CONSULT, and disconnect CONSULT from data link connector.

2. Close all doors (including back door), check that the room lamp is OFF, get out of the vehicle, and wait for

3 minutes or more with all doors closed.

CAUTION:

Never operate the vehicle while waiting.

3. Disconnect 12V battery cable from negative terminal. Refer to 

BR-6, "Precaution for Removing 12V Bat-

tery"

.

4. Disconnect the electrically-driven intelligent brake unit harness connector, then check for failures of pin

terminals and connections.