Nissan Sentra B18 (2020-2025) Service Manual: B2f70-01 Stop Lamp

Dtc Description

DTC Description

DTC DETECTION LOGIC

DTC No.	CONSULT screen items (Trouble diagnosis content)	DTC detecting condition
B2F70-01	Stop lamp (Stop lamp)	Diagnosis condition	When brake pedal is depressed
		Signal (terminal)	Brake pedal position switch signal Stop lamp switch signal
		Threshold	BCM makes a comparison between the brake pedal position switch signal and stop lamp switch signal. It judges from their values to detect the malfunctioning circuit 10 consecutive times.
		Diagnosis delay time	10 times

POSSIBLE CAUSE

• Harness or connectors

  (Brake pedal position switch circuit is open or shorted)

• Brake pedal position switch

• Fuse

• Stop lamp switch

FAIL-SAFE

—

Confirmation Procedure

Confirmation Procedure

1. PERFORM DTC CONFIRMATION PROCEDURE

   1. CONSULT

      1. Depress brake pedal 10 times.

      2. Ignition switch ON.

      3. Select “Self Diagnostic Result” mode of “BCM”.

   Is DTC detected?

   YES >>

   Refer to DTC Diagnosis Procedure.

   NO >>

   To check malfunction symptom before repair: Refer to Intermittent Incident.

   NO >>

   Confirmation after repair: Inspection End.

Dtc Diagnosis Procedure

DTC Diagnosis Procedure

1. CHECK BRAKE PEDAL POSITION SWITCH AND STOP LAMP SWITCH

   1. CONSULT

      1. Select “Brake switch 1” and “Brake switch 2” in “Data Monitor” mode of “BCM(SIGNAL BUFFER)”.

      2. Check “Brake switch 1” and “Brake switch 2” indication under the following condition.

      Monitor item	Condition		Indication
      Brake switch 1	Brake pedal	Depressed	Off
      		Not depressed	On
      Brake switch 2		Depressed	On
      		Not depressed	Off

   Is the indication normal?

   YES >>

   Brake pedal position switch and stop lamp switch is OK.

   NO >>

   Brake pedal position switch: GO TO 2.

   NO >>

   Stop lamp switch: GO TO 7.

2. CHECK FUSE

   1. Check that the following fuse is not blown (open):

      Signal name	Fuse No.	Capacity
      Ignition power supply	3	10 A

   Is the fuse blown (open)?

   YES >>

   Replace the blown (open) fuse after replacing the cause of blown (open).

   NO >>

   GO TO 3.

3. CHECK BRAKE PEDAL POSITION SWITCH SIGNAL

   1. 1. Ignition switch OFF.

      2. Disconnect BCM connector.

      3. Ignition switch ON.

      4. Check voltage between BCM harness connector and ground.

         (+)		(–)	Condition	Voltage (Approx.)
         BCM
         Connector	Terminal
         M142	111	Ground	Brake pedal is not depressed	Battery voltage
         			Brake pedal is depressed	0 V

   Is the inspection normal?

   YES >>

   Inspection End.

   NO >>

   GO TO 4.

4. CHECK BRAKE PEDAL POSITION SWITCH POWER SUPPLY CIRCUIT

   1. 1. Ignition switch OFF.

      2. Disconnect brake pedal position switch connector.

      3. Ignition switch ON.

      4. Check voltage between brake pedal position switch harness connector and ground.

         (+)		(–)	Voltage (Approx.)
         Brake pedal position switch
         Connector	Terminal
         E84	1	Ground	Battery voltage

   Is the inspection result normal?

   YES >>

   GO TO 5.

   NO >>

   Check harness for open or short between brake pedal position switch and fuse.

5. CHECK BRAKE PEDAL POSITION SWITCH SIGNAL CIRCUIT

   1. 1. Ignition switch OFF.

      2. Check continuity between brake pedal position switch harness connector and BCM harness connector.

         Brake pedal position switch		BCM		Continuity
         Connector	Terminal	Connector	Terminal
         E84	2	M142	111	Yes

      3. Check continuity between brake pedal position switch harness connector and ground.

         Brake pedal position switch		—	Continuity
         Connector	Terminal
         E84	2	Ground	No

   Is the inspection result normal?

   YES >>

   GO TO 6.

   NO >>

   Repair or replace harness.

6. CHECK BRAKE PEDAL POSITION SWITCH

   1. Refer to Component Inspection.

   Is the inspection result normal?

   YES >>

   Inspection End.

   NO >>

   Replace brake pedal position switch. Refer to Exploded View.

7. CHECK FUSE

   1. Check that the following fuse is not blown (open):

      Signal name	Fuse No.	Capacity
      Battery power supply	34	10 A

   Is the fuse blown (open)?

   YES >>

   Replace the blown (open) fuse after replacing the cause of blown (open).

   NO >>

   GO TO 8.

8. CHECK STOP LAMP SWITCH SIGNAL

   1. 1. Ignition switch OFF.

      2. Disconnect BCM connector.

      3. Check voltage between BCM harness connector and ground.

         (+)		(–)	Condition	Voltage (Approx.)
         BCM
         Connector	Terminal
         M142	110	Ground	Brake pedal is depressed	Battery voltage
         			Brake pedal is not depressed	0 V

   Is the inspection normal?

   YES >>

   Inspection End.

   NO >>

   GO TO 9.

9. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT

   1. 1. Disconnect stop lamp switch connector.

      2. Ignition switch ON.

      3. Check voltage between stop lamp switch harness connector and ground.

         (+)		(–)	Voltage (Approx.)
         Stop lamp switch
         Connector	Terminal
         E60	1	Ground	Battery voltage

   Is the inspection result normal?

   YES >>

   GO TO 10.

   NO >>

   Check harness for open or short between stop lamp switch and fuse.

10. CHECK STOP LAMP SWITCH SIGNAL CIRCUIT

    1. 1. Ignition switch OFF.

       2. Check continuity between stop lamp switch harness connector and BCM harness connector.

          Stop lamp switch		BCM		Continuity
          Connector	Terminal	Connector	Terminal
          E60	2	M142	110	Yes

       3. Check continuity between stop lamp switch harness connector and ground.

          Stop lamp switch		—	Continuity
          Connector	Terminal
          E60	2	Ground	No

    Is the inspection result normal?

    YES>>

    GO TO 11.

    NO>>

    Repair or replace harness.

11. CHECK STOP LAMP SWITCH

    1. Refer to Component Inspection.

    Is the inspection result normal?

    YES >>

    Inspection End.

    NO >>

    Replace stop lamp switch. Refer to Exploded View.