Nissan Leaf. Manual - part 277

C1AC8 BRAKE POWER SUPPLY BACKUP UNIT

BR-429

< DTC/CIRCUIT DIAGNOSIS >

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C1AC8 BRAKE POWER SUPPLY BACKUP UNIT

DTC Logic

INFOID:0000000010123087

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 “C1AC8” detected?

YES

>> Proceed to 

BR-429, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000010123088

1.

CHECK 12V BATTERY

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

DTC

Display item

Malfunction detection condition

Possible causes

C1AC8

POWER SUPPLY BACKUP 
UNIT-2

A malfunction is detected in the internal circuit of the 
brake power supply backup unit.

• Harness or connector
• Fuse
• Brake power supply backup 

unit

• Electrically-driven intelligent 

brake unit

BR-430

< DTC/CIRCUIT DIAGNOSIS >

C1AC8 BRAKE POWER SUPPLY BACKUP UNIT

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 “C1AC8” 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.

5. Disconnect the brake power supply backup unit harness connector, then check for failures of pin terminals

and connections.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace error-detected parts and GO TO 4.

C1AC8 BRAKE POWER SUPPLY BACKUP UNIT

BR-431

< DTC/CIRCUIT DIAGNOSIS >

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4.

PERFORM SELF-DIAGNOSIS (2)

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.

7. 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.

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

CAUTION:

Never set the vehicle to READY.

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

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

11. 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.

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

CAUTION:

Never set the vehicle to READY.

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

14. Release brake pedal.

15. Start CONSULT and perform “BRAKE” self-diagnosis.
Is DTC “C1AC8” detected?

YES

>> GO TO 5.

NO

>> INSPECTION END

5.

CHECK POWER SWITCH ON POWER SUPPLY 

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

2. Connect 12V battery cable to negative terminal.

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

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

tery"

.

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

7. Connect 12V battery cable to negative terminal.

8. Check the voltage between the electrically-driven intelligent brake unit harness connector and ground.

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

CAUTION:

Never set the vehicle to READY.

10. Check the voltage between the electrically-driven intelligent brake unit harness connector and ground.

Electrically-driven intelligent brake unit

—

Voltage

(Approx.)

Connector

Terminal

E34

26

Ground

0 V

BR-432

< DTC/CIRCUIT DIAGNOSIS >

C1AC8 BRAKE POWER SUPPLY BACKUP UNIT

Is the inspection result normal?

YES

>> GO TO 8.

NO

>> GO TO 6.

6.

CHECK POWER SWITCH ON 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. Disconnect 12V battery cable from negative terminal. Refer to 

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

tery"

.

4. Check the 15A fuse (#62).

5. Disconnect IPDM E/R harness connector.

6. Check the continuity between electrically-driven intelligent brake unit and IPDM E/R.

7. Check the continuity between electrically-driven intelligent brake unit harness connector and ground.

Is the inspection result normal?

YES

>> Perform trouble diagnosis for power ON power supply. Refer to 

PG-26, "Wiring Diagram—On

Power Supply—"

.

NO

>> Repair or replace error-detected parts and GO TO 7.

7.

PERFORM SELF-DIAGNOSIS (3)

With CONSULT

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

2. Connect IPDM E/R 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.

7. 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.

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

CAUTION:

Never set the vehicle to READY.

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

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

11. 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.

Electrically-driven intelligent brake unit

—

Voltage

(Approx.)

Connector

Terminal

E34

26

Ground

10 

− 16 V

Electrically-driven intelligent brake unit

IPDM E/R

Continuity

Connector

Terminal

Connector

Terminal

E34

26

E15

62

Existed

Electrically-driven intelligent brake unit

—

Continuity

Connector

Terminal

E34

26

Ground

Not existed