Nissan Pathfinder: System Description - Component Parts ++

Brake Control System Component Parts Location

 

A.	Steering column area	B.	Engine room (RH)	C.	Engine room (LH)
D.	Front left wheel	E.	Engine room (LH)	F.	Brake pedal area
G.	Center console area	H.	Rear left wheel

No.	Component		Function
1.	ADAS (Advanced Driver Assistance System) control unit 2		Control each system, based on CAN communication and ITS communication signals received from each control unit Transmits signals necessary for control between CAN communication and ITS communication Refer to Component Parts Location for detailed component location.
2.	Chassis control module		Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication: Drive mode signal Active Trace Control signal Brake hold status signal Brake hold request signal Refer to Component Parts Location for detailed component location.
3.	Combination meter		Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication: Brake fluid level switch signal Electric 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 OFF indicator lamp signal VDC warning lamp signal Refer to Component Part Location (7 Inch Information Display) for detailed component location.
4.	Steering angle sensor		Transmits the steering angle sensor malfunction signal to ADAS control unit 2, 4WD control unit, Chassis control unit ABS actuator and electric unit (control unit) and AV control unit via CAN communication. Refer to Steering Angle Sensor.
5.	ABS (Anti-lock Braking System) actuator and electric unit (control unit)		Refer to ABS Actuator and Electric Unit (Control Unit).
6.	Brake fluid level switch		Refer to Brake Fluid Level Switch.
7.	Front wheel sensor LH (RH similar)		Refer to Wheel Sensor and Sensor Rotor.
8.	Vacuum sensor		Refer to Vacuum Sensor.
9.	Brake pedal position switch		Refer to Brake Pedal Position Switch.
10.	Stop lamp switch		Refer to Stop Lamp Switch.
11.	Electric parking brake switch		Refer to Component Parts Location.
12.	Auto brake hold switch		Refer to Component Parts Location.
13.	Rear wheel sensor LH (RH similar)		Refer to Wheel Sensor and Sensor Rotor.

ABS Actuator and Electric Unit (Control Unit)

FUNCTIONS WITHIN THE SYSTEM

Electric unit (control unit) is integrated with actuator and comprehensively controls VDC function, TCS function, ABS function, EBD function, Active brake limited slip (ABLS) function, Brake assist function, brake force distribution function, hill start assist function and electric parking brake function.

INDIVIDUAL FUNCTIONS WITHIN THE SYSTEM

ELECTRIC UNIT (CONTROL UNIT)

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

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

ACTUATOR

The following components are integrated with ABS actuator.

Pump

• Pressure the brake fluid and send.

• 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

Switches the fluid pressure line to increase or hold according to signals from control unit.

NOTE:

Valve is a solenoid valve.

 

ABS Out Valve

Switches the fluid pressure line to increase, hold or decrease according to signals from control unit.

NOTE:

Valve is a solenoid valve.

 

Cut Valve 1, Cut Valve 2

Shuts off the ordinary brake line from master cylinder, when VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function are activated.

NOTE:

Valve is a solenoid valve.

 

Suction Valve 1, Suction Valve 2

Supplies the brake fluid from master cylinder to the pump, when VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function are activated.

NOTE:

Valve is a solenoid valve.

 

Inlet Valve

Brake fluid sucked from the reservoir by the pump does not backflow.

NOTE:

Valve is a solenoid valve.

 

Outlet Valve

Brake fluid discharged from the pump does not backflow.

NOTE:

Valve is a solenoid valve.

 

Return Check Valve

Returns the brake fluid from brake caliper to master cylinder by bypassing orifice of each valve when brake is released.

Reservoir

Temporarily reserves the brake fluid drained from brake caliper and wheel cylinder, so that pressure efficiently decreases when decreasing pressure of brake caliper.

Yaw Rate/Side/Decel G Sensor

Calculates the following information that affects the vehicle, and transmits a signal to ABS actuator and electric unit (control unit) via communication lines. [Yaw rate/side/decel G sensor is integrated in ABS actuator and electric unit (control unit).]

• Vehicle rotation angular velocity (yaw rate signal)

• Vehicle lateral acceleration (side G signal) and longitudinal acceleration (decel G signal)

Pressure Sensor

Detects the brake fluid pressure and transmits signal to ABS actuator and electric unit (control unit). [Pressure sensor is integrated in ABS actuator and electric unit (control unit).]

INDIVIDUAL OPERATION

• Brake fluid pressure, and traction motor are controlled according to signals from each sensor.

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

PARTS LOCATION

Refer to Component Parts Location.

Wheel Sensor and Sensor Rotor

FUNCTIONS WITHIN THE SYSTEM

Wheel sensor and sensor rotor detect each wheel speed. And wheel sensor inputs wheel speed signal to ABS actuator and electric unit (control unit).

INDIVIDUAL FUNCTIONS WITHIN THE SYSTEM

The wheel sensor reads a magnetic field change.

INDIVIDUAL OPERATION

• Downsize and weight reduction is aimed. IC for detection portion and magnet for sensor rotor are adopted.

  

• 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.

PARTS LOCATION

Refer to Component Parts Location.

Steering Angle Sensor

FUNCTIONS WITHIN THE SYSTEM

Steering angle sensor transmits steering angle sensor signal to ABS actuator and electric unit (control unit) via CAN communication.

INDIVIDUAL FUNCTIONS WITHIN THE SYSTEM

Steering angle sensor detects the following status.

• Steering wheel rotation amount

• Steering wheel rotation angular velocity

• Steering wheel rotation direction

INDIVIDUAL OPERATION

Steering angle sensor converts the rotation amount, rotation angular velocity and rotation direction of the steering wheel as the steering angle sensor signal.

PARTS LOCATION

Refer to Component Parts Location.

Brake Fluid Level Switch

FUNCTIONS WITHIN THE SYSTEM

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.

INDIVIDUAL FUNCTIONS WITHIN THE SYSTEM

Brake fluid level switch detects the brake fluid level in reservoir tank.

INDIVIDUAL OPERATION

• The switch is turned ON when brake fluid level is the specified level or less.

  

• Ground is supplied as the switch signal to the control unit when the switch is ON.

PARTS LOCATION

Refer to Component Parts Location.

Brake Vacuum Sensor

FUNCTIONS WITHIN THE SYSTEM

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

INDIVIDUAL FUNCTIONS WITHIN THE SYSTEM

Detects the vacuum in brake booster.

INDIVIDUAL OPERATION

Brake vacuum sensor converts the brake vacuum sensor signal.

PARTS LOCATION

Refer to Component Parts Location.

Integral Switch (VDC OFF signal)

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

  

  • VDC function

  • TCS function

  • Active trace control function

NOTE:

VDC OFF switch is a menu selection in the integral switch.

 

NOTE:

ABS function and EBD function control operates.

 

• VDC OFF indicator 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).