Nissan Leaf. Manual - part 286

U1511 BRAKE POWER SUPPLY BACKUP UNIT COMMUNICATION

BR-465

< DTC/CIRCUIT DIAGNOSIS >

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7. Check the 15A fuse (#75).

8. Check the continuity and for short circuit between harness connector terminal 28 of electrically-driven

intelligent brake unit and 15A fuse (#75).

Is the inspection result normal?

YES

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

PG-15, "Wiring Diagram — Bat-

tery Power Supply —"

.

NO

>> Repair or replace error-detected parts and GO TO 10.

10.

PERFORM SELF-DIAGNOSIS (4)

With CONSULT

1. Connect the electrically-driven intelligent brake unit harness connector.

2. Connect 12V battery cable to negative terminal.

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

CAUTION:

Never set the vehicle to READY.

4. Repeat step 3 two or more times.

CAUTION:

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

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

6. 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.

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

CAUTION:

Never set the vehicle to READY.

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

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

10. 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.

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

CAUTION:

Never set the vehicle to READY.

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

13. Release brake pedal.

14. Start CONSULT and perform “BRAKE” self-diagnosis.
Is DTC “U1511” detected?

YES

>> GO TO 11.

NO

>> INSPECTION END

11.

CHECK GROUND 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. 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. Check the continuity between electrically-driven intelligent brake unit and ground.

Is the inspection result normal?

YES

>> GO TO 13.

Electrically-driven intelligent brake unit

—

Continuity

Connector

Terminal

E34

32

Ground

Existed

BR-466

< DTC/CIRCUIT DIAGNOSIS >

U1511 BRAKE POWER SUPPLY BACKUP UNIT COMMUNICATION

NO

>> Repair or replace error-detected parts and GO TO 12.

12.

PERFORM SELF-DIAGNOSIS (5)

With CONSULT

1. Connect the electrically-driven intelligent brake unit harness connector.

2. Connect 12V battery cable to negative terminal.

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

CAUTION:

Never set the vehicle to READY.

4. Repeat step 3 two or more times.

CAUTION:

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

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

6. 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.

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

CAUTION:

Never set the vehicle to READY.

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

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

10. 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.

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

CAUTION:

Never set the vehicle to READY.

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

13. Release brake pedal.

14. Start CONSULT and perform “BRAKE” self-diagnosis.
Is DTC “U1511” detected?

YES

>> GO TO 13.

NO

>> INSPECTION END

13.

CHECK DATA MONITOR (1)

With CONSULT

1. Connect the electrically-driven intelligent brake unit harness connector.

2. Connect 12V battery cable to negative terminal.

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

CAUTION:

Never set the vehicle to READY.

4. Repeat step 3 two or more times.

CAUTION:

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

5. Start CONSULT and select “BRAKE”, “DATE MONITOR” according this order.

6. Check the “MOTOR POWER SUPPLY” and “CONTROL MODULE POWER”. Refer to 

BR-33, "Reference

Value"

.

Is the inspection result normal?

YES

>> GO TO 14.

NO

>> Replace the electrically-driven intelligent brake unit. Refer to 

BR-510, "Removal and installation"

.

14.

PERFORM SELF-DIAGNOSIS (6)

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:

U1511 BRAKE POWER SUPPLY BACKUP UNIT COMMUNICATION

BR-467

< DTC/CIRCUIT DIAGNOSIS >

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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 “U1511” detected?

YES

>> GO TO 15.

NO

>> INSPECTION END

15.

CHECK BRAKE POWER SUPPLY BACKUP UNIT 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. 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 electrically-driven intelligent brake unit and ground.

Electrically-driven intelligent brake unit

Brake power supply backup unit

Continuity

Connector

Terminal

Connector

Terminal

E34

31

B15

1

Existed

31

4

Not existed

31

5

Not existed

22

1

Not existed

22

4

Existed

22

5

Not existed

37

1

Not existed

37

4

Not existed

37

5

Existed

BR-468

< DTC/CIRCUIT DIAGNOSIS >

U1511 BRAKE POWER SUPPLY BACKUP UNIT COMMUNICATION

Is the inspection result normal?

YES

>> GO TO 16.

NO

>> Repair or replace error-detected parts.

16.

CHECK BRAKE POWER SUPPLY BACKUP UNIT POWER SUPPLY 

1. Connect 12V battery cable to negative terminal.

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

Is the inspection result normal?

YES

>> GO TO 18.

NO

>> GO TO 17.

17.

CHECK BRAKE POWER SUPPLY BACKUP UNIT POWER SUPPLY CIRCUIT 

1. Turn the power switch OFF to exit CONSULT.

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

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

tery"

.

3. Check the 15A fuse (#82).

4. 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 18.

NO

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

PG-15, "Wiring Diagram — Bat-

tery Power Supply —"

.

18.

PERFORM SELF-DIAGNOSIS (7)

With CONSULT

1. Connect the electrically-driven intelligent brake unit harness connector.

2. Connect the brake power supply backup unit harness connector.

3. Connect 12V battery cable to negative terminal.

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

CAUTION:

Never set the vehicle to READY.

5. Repeat step 4 two or more times.

CAUTION:

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

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

Electrically-driven intelligent brake unit

—

Continuity

Connector

Terminal

E34

31

Ground

Not existed

22

Not existed

37

Not existed

32

Existed

Brake power supply backup unit

—

Voltage

(Approx.)

Connector

Terminal

B15

6

Ground

10 

− 16 V

Brake power supply backup unit

—

Voltage

(Approx.)

Connector

Terminal

B15

6

Ground

10 

− 16 V