Nissan Sentra B18 (2020-2025) Service Manual: Component Parts

Brake Control System

Component Parts Location

Component Parts Location

A.	Right side of engine compartment	B.	Left side of engine compartment	C.	Left front wheel area (RH similar)
D.	Brake pedal area	E.	Left side of instrument panel (view with component removed from Nissan Sentra vehicle)	F.	Left side of instrument panel (view with component removed from Nissan Sentra vehicle)
G.	Steering wheel area (view with steering wheel removed)	H.	Left rear wheel area (RH similar)

No.	Component	Function
1.	BCM (Body Control Module)	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication: Stop lamp switch signal Brake pedal position switch signal Ignition switch ON signal Refer to Component Parts Location for detailed component location.
2.	ABS (Anti-lock Braking System) actuator and electric unit (control unit)	Refer to ABS Actuator and Electric Unit (Control Unit).
3.	Brake fluid level switch	Refer to Brake Fluid Level Switch.
4.	Vacuum sensor	Refer to Vacuum Sensor.
5.	Front wheel sensor LH (RH similar)	Refer to Wheel Sensor and Sensor Rotor.
6.	Brake pedal position switch	Detects the operation status of brake pedal and transmits converted electric signal to ABS actuator and electric unit (control unit).
7.	Stop lamp switch	Refer to Stop Lamp Switch.
8.	Combination meter	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication: Brake fluid level switch signal Parking brake switch signal Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication: ABS warning lamp signal Brake warning lamp signal VDC (Nissan Sentra Vehicle Dynamic Control) OFF indicator lamp signal VDC OFF signal Slip indicator lamp (VDC warning lamp) signal Refer to Combination Meter (VDC OFF signal).
9.	Chassis control module (with built in steering angle sensor)	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication: Steering angle sensor signal Steering angle sensor malfunction signal Intelligent trace control signal Active ride control signal Refer to Chassis Control Module (With Built In Steering Angle Sensor) for detailed component location.
10.	Rear wheel sensor LH (RH similar)	Refer to Wheel Sensor and Sensor Rotor.

Wheel Sensor and Sensor Rotor

Wheel Sensor and Sensor Rotor Note:

• Wheel sensor of front wheel is installed on steering knuckle.

  

• Sensor rotor of front wheel is integrated into the wheel hub assembly.

• Wheel sensor of rear wheel is installed on rear final drive.

• Sensor rotor of rear wheel is installed on drive shaft (rear final drive side).

• Never measure resistance and voltage value using a tester because sensor is an active sensor.

• Power supply is supplied to detection portion so that magnetic field line is read. Magnetic field that is detected is converted to current signal.

  

• When sensor rotor rotates, magnetic field changes. Magnetic field change is converted to current signals (rectangular wave) and is transmitted to ABS actuator and electric unit (control unit). Change of magnetic field is proportional to wheel speed.

Abs Actuator and Electric Unit (control Unit)

ABS Actuator and Electric Unit (Control Unit)

The ABS actuator and electric unit (control unit) is located the right side of the engine room.

Electric unit (control unit) is integrated with actuator and comprehensively controls VDC function, TCS (Traction Control System) function, ABS function, EBD (Electric Brake Distribution) function and brake assist function.

ELECTRIC UNIT (CONTROL UNIT)

• Brake fluid pressure, engine and transmission are controlled according to signals from each sensor.

• If malfunction is detected, the system enters fail-safe mode.

ACTUATOR

The following components are integrated with ABS actuator:

Pump

Returns the brake fluid reserved in reservoir to master cylinder by reducing pressure.

Motor

Activates the pump according to signals from ABS actuator and electric unit (control unit).

Motor Relay

Operates the motor ON/OFF according to signals from ABS actuator and electric unit (control unit).

Actuator Relay

Operates each valve ON/OFF according to signals from ABS actuator and electric unit (control unit).

ABS IN Valve and ABS OUT Valve

Increases, holds or decreases the fluid pressure of each caliper according to signals from ABS actuator and electric unit (control unit).

Pressure Sensor

Detects the brake fluid pressure and transmits signal to ABS actuator and electric unit (control unit).

Cut Valve 1 (Primary Line) and Cut Valve 2 (Secondary Line)

Shuts off the ordinary brake line from master cylinder when VDC function, TCS function and brake assist function are activated.

Yaw Rate/Side/Decel G Sensor

Calculates the following information that affects the Nissan Sentra vehicle and transmits a signal to ABS actuator and electric unit (control unit): [Yaw rate/side/decel G sensor is integrated into the ABS actuator and electric unit (control unit).]

• Nissan Sentra Vehicle rotation angular velocity (yaw rate signal)

• Vehicle lateral acceleration (side G signal)

• Nissan Sentra Vehicle longitudinal acceleration (decel G signal)

Stop Lamp Switch

Stop Lamp Switch

The stop lamp switch is attached to the brake pedal bracket near the brake pedal.

Detects the operation status of brake pedal and transmits converted electric signal to ABS actuator and electric unit (control unit).

Steering Angle Sensor

Steering Angle Sensor

The chassis control module (with built in steering angle sensor) is located behind the steering wheel.

Detects the following information and transmits steering angle signal to ABS actuator and electric unit (control unit) via CAN communication:

• Chassis control module (with built in steering angle sensor) malfunction signal

• Steering wheel rotation amount

• Steering wheel rotation angular velocity

• Steering wheel rotation direction

• Intelligent trace control signal

Brake Fluid Level Switch

Brake Fluid Level Switch

The brake fluid level switch is located on the left side of the master cylinder reservoir.

Detects the brake fluid level in reservoir tank and transmits converted electric signal from combination meter to ABS actuator and electric unit (control unit) via CAN communication when brake fluid level is the specified level or less.

Combination Meter (vdc Off Signal)

Combination meter (VDC OFF Signal)

• Non-operational status or standby status of the following functions can be selected using VDC OFF switch: VDC OFF indicator lamp indicates the operation status of function (ON: Non-operational status, OFF: Standby status).

  • Type A meter
  • Type B meter

  • Nissan Sentra Vehicle Dynamic Control function

  • Traction Control System function

  • Automatic Emergency Braking function

Note:

ABS function and EBD function operate.

• VDC OFF indicator lamp turns OFF (standby status) when the engine is started again after it is stopped once while VDC OFF indicator lamp is ON (non-operational status).

Vacuum Sensor

Vacuum Sensor

The brake fluid level switch is located on the left side of the brake booster.

Detects the vacuum in brake booster and transmits converted electric signal to ABS actuator and electric unit (control unit).