Nissan Pathfinder: System Description - System ++

System Description

• The system switches fluid pressure of each brake to increase, to hold or to decrease according to signals from control unit in ABS actuator and electric unit (control unit). This control system is applied to VDC function, TCS function, ABS function, EBD function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function.

• Fail-safe function is available for each function and is activated by each function when system malfunction occurs.

SYSTEM DIAGRAM

NOTE:

• 4WD control unit is applied to 4WD models.

 

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
ABS actuator and electric unit (control unit)	ABS Actuator and Electric Unit (Control Unit)
Front LH wheel sensor	Wheel Sensor and Sensor Rotor
Front RH wheel sensor	Wheel Sensor and Sensor Rotor
Rear LH wheel sensor	Wheel Sensor and Sensor Rotor
Rear RH wheel sensor	Wheel Sensor and Sensor Rotor
Brake vacuum sensor	Brake Vacuum Sensor
Parking brake switch	Parking Brake Switch
Parking brake actuator (LH)	Parking Brake Actuator
Parking brake actuator (RH)	Parking Brake Actuator
ECM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Accelerator pedal position signal Engine speed signal Engine torque signal
TCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Current gear position signal A/T accept permission signal Shift position signal
BCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Stop lamp switch signal Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication. Stop lamp request signal
IPDM E/R	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Ignition switch ON signal
Chassis control module	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Active ride control signal Automatic brake hold operation request signal Automatic brake hold release request signal Chassis control module malfunction signal Electric parking brake operation request signal Intelligent trace control signal
Steering angle sensor	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Steering angle sensor signal
Combination meter	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Brake fluid level 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 Electric parking brake indicator lamp signal Electric parking brake warning lamp signal VDC OFF indicator lamp signal VDC warning lamp signal

VALVE OPERATION [VDC FUNCTION, TCS FUNCTION, ACTIVE BRAKE LIMITED SLIP (ABLS) FUNCTION, BRAKE ASSIST FUNCTION, BRAKE FORCE DISTRIBUTION FUNCTION, hill start assist FUNCTION

Each valve is operated and fluid pressure of brake is controlled.

VDC Function, TCS Function, Active Brake Limited Slip (ABLS) Function, Brake Assist Function, Brake force distribution Function, and hill start assist Function are in Operation (During Pressure Increases)

Component	Not activated	When pressure increases
Cut valve 1	Power supply is not supplied (open)	Power supply is supplied (close)
Cut valve 2	Power supply is not supplied (open)	Power supply is supplied (close)
Suction valve 1	Power supply is not supplied (close)	Power supply is supplied (open)
Suction valve 2	Power supply is not supplied (close)	Power supply is supplied (open)
ABS IN valve	Power supply is not supplied (open)	Power supply is not supplied (open)
ABS OUT valve	Power supply is not supplied (close)	Power supply is not supplied (close)
Each brake (fluid pressure)	—	Pressure increases

 

During pressure front RH brake increases

• Brake fluid is conveyed to the pump from the master cylinder through suction valve 1 and is pressurized by the pump operation. The pressurized brake fluid is supplied to the front RH brake through the ABS IN valve. For the left brake, brake fluid pressure is maintained because the pressurization is unnecessary. The pressurization for the left brake is controlled separately from the right brake.

During pressure front LH brake increases

• Brake fluid is conveyed to the pump from the master cylinder through suction valve 2 and is pressurized by the pump operation. The pressurized brake fluid is supplied to the front LH brake through the ABS IN valve. For the right brake, brake fluid pressure is maintained because the pressurization is unnecessary. The pressurization for the right brake is controlled separately from the left brake.

During pressure rear RH brake increases

• Brake fluid is conveyed to the pump from the master cylinder through suction valve 2 and is pressurized by the pump operation. The pressurized brake fluid is supplied to the rear RH brake through the ABS IN valve. For the left brake, brake fluid pressure is maintained because the pressurization is unnecessary. The pressurization for the left brake is controlled separately from the right brake.

During pressure rear LH brake increases

• Brake fluid is conveyed to the pump from the master cylinder through suction valve 1 and is pressurized by the pump operation. The pressurized brake fluid is supplied to the rear LH brake through the ABS IN valve. For the right brake, brake fluid pressure is maintained because the pressurization is unnecessary. The pressurization for the right brake is controlled separately from the left brake.

VDC Function, TCS Function, Active Brake Limited Slip (ABLS) Function, Brake Assist Function, Brake force distribution Function, and hill start assist Function are in Operation (During Pressure Holds)

Component	Not activated	When pressure holds
Cut valve 1	Power supply is not supplied (open)	Power supply is supplied (close)
Cut valve 2	Power supply is not supplied (open)	Power supply is supplied (close)
Suction valve 1	Power supply is not supplied (close)	Power supply is not supplied (close)
Suction valve 2	Power supply is not supplied (close)	Power supply is not supplied (close)
ABS IN valve	Power supply is not supplied (open)	Power supply is not supplied (open)
ABS OUT valve	Power supply is not supplied (close)	Power supply is not supplied (close)
Each brake (fluid pressure)	—	Pressure holds

 

During pressure front RH brake holds

• Since the cut valve 1 and the suction valve 1 are closed, the front RH brake, master cylinder, and reservoir are blocked. This maintains fluid pressure applied on the front RH brake. The pressurization for the left brake is controlled separately from the right brake.

During pressure front LH brake holds

• Since the cut valve 2 and the suction valve 2 are closed, the front LH brake, master cylinder, and reservoir are blocked. This maintains fluid pressure applied on the front LH brake. The pressurization for the right brake is controlled separately from the left brake.

During pressure rear RH brake holds

• Since the cut valve 2 and the suction valve 2 are closed, the rear RH brake, master cylinder, and reservoir are blocked. This maintains fluid pressure applied on the rear RH brake. The pressurization for the left brake is controlled separately from the right brake.

During pressure rear LH brake holds

• Since the cut valve 1 and the suction valve 1 are closed, the rear LH brake, master cylinder, and reservoir are blocked. This maintains fluid pressure applied on the rear LH brake. The pressurization for the right brake is controlled separately from the left brake.

VDC Function, TCS Function, Active Brake Limited Slip (ABLS) Function, Brake Assist Function, Brake force distribution Function, and hill start assist Function are in Operation (During Pressure Decrease)

Component	Not activated	When pressure decrease
Cut valve 1	Power supply is not supplied (open)	Power supply is not supplied (open)
Cut valve 2	Power supply is not supplied (open)	Power supply is not supplied (open)
Suction valve 1	Power supply is not supplied (close)	Power supply is not supplied (close)
Suction valve 2	Power supply is not supplied (close)	Power supply is not supplied (close)
ABS IN valve	Power supply is not supplied (open)	Power supply is not supplied (open)
ABS OUT valve	Power supply is not supplied (close)	Power supply is not supplied (close)
Each brake (fluid pressure)	—	Pressure decreases

 

During pressure front RH brake decreased

• Since the suction valve 1 and the ABS OUT valve close and the cut valve 1 and the ABS IN valve open, the fluid pressure applied on the front RH brake is reduced by supplying the fluid pressure to the master cylinder via the ABS IN valve and the cut valve 1. The pressurization for the right brake is controlled separately from the left brake.

During pressure front LH brake decreased

• Since the suction valve 2 and the ABS OUT valve close and the cut valve 2 and the ABS IN valve open, the fluid pressure applied on the front LH brake is reduced by supplying the fluid pressure to the master cylinder via the ABS IN valve and the cut valve 2. The pressurization for the left brake is controlled separately from the right brake.

During pressure rear RH brake decreased

• Since the suction valve 2 and the ABS OUT valve close and the cut valve 2 and the ABS IN valve open, the fluid pressure applied on the rear RH brake is reduced by supplying the fluid pressure to the master cylinder via the ABS IN valve and the cut valve 2. The pressurization for the right brake is controlled separately from the left brake.

During pressure rear LH brake decreased

• Since the suction valve 1 and the ABS OUT valve close and the cut valve 1 and the ABS IN valve open, the fluid pressure applied on the rear LH brake is reduced by supplying the fluid pressure to the master cylinder via the ABS IN valve and the cut valve 1. The pressurization for the left brake is controlled separately from the right brake.

Component Parts and Function

Component	Function
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).
Cut valve 1 Cut valve 2	Shuts off the ordinary brake line from master cylinder.
Suction valve 1 Suction valve 2	Supplies the brake fluid from master cylinder to the pump.
ABS IN valve	Switches the fluid pressure line to increase or hold according.
ABS OUT valve	Switches the fluid pressure line to increase, hold or decrease according.
return check valve	Returns the brake fluid from each brake to master cylinder by bypassing orifice of each valve when brake is released.
Reservoir	Temporarily reserves the brake fluid drained from each brake, so that pressure efficiently decreases when decreasing pressure of each brake.
Pressure sensor	Detects the brake fluid pressure and transmits signal to ABS actuator and electric unit (control unit).

VALVE OPERATION (ABS FUNCTION)

Each valve is operated and fluid pressure of brake is controlled.

When Brake Pedal is Applied

Component	Not activated	When pressure increases
Cut valve 1	Power supply is not supplied (open)	Power supply is not supplied (open)
Cut valve 2	Power supply is not supplied (open)	Power supply is not supplied (open)
Suction valve 1	Power supply is not supplied (close)	Power supply is not supplied (close)
Suction valve 2	Power supply is not supplied (close)	Power supply is not supplied (close)
ABS IN valve	Power supply is not supplied (open)	Power supply is not supplied (open)
ABS OUT valve	Power supply is not supplied (close)	Power supply is not supplied (close)
Each brake (fluid pressure)	—	Pressure increases

 

During pressure front RH brake increases

• When the cut valve 1 and the ABS IN valve opens, brake fluid is supplied to the front RH brake from the master cylinder through the ABS IN valve. Brake fluid does not flow into the reservoir because the ABS OUT valve is closed.

During pressure front LH brake increases

• When the cut valve 2 and the ABS IN valve opens, brake fluid is supplied to the front LH brake from the master cylinder through the ABS IN valve. Brake fluid does not flow into the reservoir because the ABS OUT valve is closed.

During pressure rear RH brake increases

• When the cut valve 2 and the ABS IN valve opens, brake fluid is supplied to the rear RH brake from the master cylinder through the ABS IN valve. Brake fluid does not flow into the reservoir because the ABS OUT valve is closed.

During pressure rear LH brake increases

• When the cut valve 1 and the ABS IN valve opens, brake fluid is supplied to the rear LH brake from the master cylinder through the ABS IN valve. Brake fluid does not flow into the reservoir because the ABS OUT valve is closed.

When ABS Function is in Operation (During Pressure Increases)

Component	Not activated	When pressure increases
Cut valve 1	Power supply is not supplied (open)	Power supply is not supplied (open)
Cut valve 2	Power supply is not supplied (open)	Power supply is not supplied (open)
Suction valve 1	Power supply is not supplied (close)	Power supply is not supplied (close)
Suction valve 2	Power supply is not supplied (close)	Power supply is not supplied (close)
ABS IN valve	Power supply is not supplied (open)	Power supply is not supplied (open)
ABS OUT valve	Power supply is not supplied (close)	Power supply is not supplied (close)
Each brake (fluid pressure)	—	Pressure increases

 

During pressure front RH brake increases

• Brake fluid is supplied to the front RH brake from the master cylinder through the cut valve 1 and the ABS IN valve. Since the suction valve 1 and the ABS OUT valve is closed, the fluid does not flow into the reservoir. The amount of brake fluid supplied to the front RH brake from the master cylinder is controlled according to time that the ABS IN valve is not energized (time that the ABS IN valve is open).

During pressure front LH brake increases

• Brake fluid is supplied to the front LH brake from the master cylinder through the cut valve 2 and the ABS IN valve. Since the suction valve 2 and the ABS OUT valve is closed, the fluid does not flow into the reservoir. The amount of brake fluid supplied to the front LH brake from the master cylinder is controlled according to time that the ABS IN valve is not energized (time that the ABS IN valve is open).

During pressure rear RH brake increases

• Brake fluid is supplied to the rear RH brake from the master cylinder through the cut valve 2 and the ABS IN valve. Since the suction valve 2 and the ABS OUT valve is closed, the fluid does not flow into the reservoir. The amount of brake fluid supplied to the rear RH brake from the master cylinder is controlled according to time that the ABS IN valve is not energized (time that the ABS IN valve is open).

During pressure rear LH brake increases

• Brake fluid is supplied to the rear LH brake from the master cylinder through the cut valve 1 and the ABS IN valve. Since the suction valve 1 and the ABS OUT valve is closed, the fluid does not flow into the reservoir. The amount of brake fluid supplied to the rear LH brake from the master cylinder is controlled according to time that the ABS IN valve is not energized (time that the ABS IN valve is open).

When ABS Function is Operating (During Pressure Holds)

Component	Not activated	When pressure holds
Cut valve 1	Power supply is not supplied (open)	Power supply is not supplied (open)
Cut valve 2	Power supply is not supplied (open)	Power supply is not supplied (open)
Suction valve 1	Power supply is not supplied (close)	Power supply is not supplied (close)
Suction valve 2	Power supply is not supplied (close)	Power supply is not supplied (close)
ABS IN valve	Power supply is not supplied (open)	Power supply is supplied (close)
ABS OUT valve	Power supply is not supplied (close)	Power supply is not supplied (close)
Each brake (fluid pressure)	—	Pressure holds

 

During pressure front RH brake holds

• Since the ABS IN valve and the ABS OUT valve are closed, the front RH brake, master cylinder, and reservoir are blocked. This maintains fluid pressure applied on the front RH brake.

During pressure front LH brake holds

• Since the ABS IN valve and the ABS OUT valve are closed, the front LH brake, master cylinder, and reservoir are blocked. This maintains fluid pressure applied on the front LH brake.

During pressure rear RH brake holds

• Since the ABS IN valve and the ABS OUT valve are closed, the rear RH brake, master cylinder, and reservoir are blocked. This maintains fluid pressure applied on the rear RH brake.

During pressure rear LH brake holds

• Since the ABS IN valve and the ABS OUT valve are closed, the rear LH brake, master cylinder, and reservoir are blocked. This maintains fluid pressure applied on the rear LH brake.

When ABS Function is in Operation (During Pressure Decreases)

Component	Not activated	When pressure decreases
Cut valve 1	Power supply is not supplied (open)	Power supply is not supplied (open)
Cut valve 2	Power supply is not supplied (open)	Power supply is not supplied (open)
Suction valve 1	Power supply is not supplied (close)	Power supply is not supplied (close)
Suction valve 2	Power supply is not supplied (close)	Power supply is not supplied (close)
ABS IN valve	Power supply is not supplied (open)	Power supply is supplied (close)
ABS OUT valve	Power supply is not supplied (close)	Power supply is supplied (open)
Each brake (fluid pressure)	—	Pressure decreases

During pressure front RH brake decreased

• Since the ABS IN valve is closed and the ABS OUT valve is opened, fluid pressure applied on the front RH brake is supplied to the reservoir through the ABS OUT valve. This fluid pressure decreases when sent to the master cylinder by the pump.

During pressure front LH brake decreased

• Since the ABS IN valve is closed and the ABS OUT valve is opened, fluid pressure applied on the front LH brake is supplied to the reservoir through the ABS OUT valve. This fluid pressure decreases when sent to the master cylinder by the pump.

During pressure rear RH brake decreased

• Since the ABS IN valve is closed and the ABS OUT valve is opened, fluid pressure applied on the rear RH brake is supplied to the reservoir through the ABS OUT valve. This fluid pressure decreases when sent to the master cylinder by the pump.

During pressure rear LH brake decreased

• Since the ABS IN valve is closed and the ABS OUT valve is opened, fluid pressure applied on the rear LH brake is supplied to the reservoir through the ABS OUT valve. This fluid pressure decreases when sent to the master cylinder by the pump.

When Brake Release

Component	Not activated	When pressure decrease
Cut valve 1	Power supply is not supplied (open)	Power supply is not supplied (open)
Cut valve 2	Power supply is not supplied (open)	Power supply is not supplied (open)
Suction valve 1	Power supply is not supplied (close)	Power supply is not supplied (close)
Suction valve 2	Power supply is not supplied (close)	Power supply is not supplied (close)
ABS IN valve	Power supply is not supplied (open)	Power supply is not supplied (open)
ABS OUT valve	Power supply is not supplied (close)	Power supply is not supplied (close)
Each brake (fluid pressure)	—	Pressure decreases

 

During pressure front RH brake release

• Brake fluid is supplied to the front RH brake through the return check valve of the ABS IN valve and the cut valve 1, and returns to the master cylinder.

During pressure front LH brake release

• Brake fluid is supplied to the front LH brake through the return check valve of the ABS IN valve and the cut valve 2, and returns to the master cylinder.

During pressure rear RH brake release

• Brake fluid is supplied to the rear RH brake through the return check valve of the ABS IN valve and the cut valve 2, and returns to the master cylinder.

During pressure rear LH brake release

• Brake fluid is supplied to the rear LH brake through the return check valve of the ABS IN valve and the cut valve 1, and returns to the master cylinder.

Component Parts and Function

Component	Function
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).
Cut valve 1 Cut valve 2	Shuts off the ordinary brake line from master cylinder.
Suction valve 1 Suction valve 2	Supplies the brake fluid from master cylinder to the pump.
ABS IN valve	Switches the fluid pressure line to increase or hold according.
ABS OUT valve	Switches the fluid pressure line to increase, hold or decrease according.
return check valve	Returns the brake fluid from each brake to master cylinder by bypassing orifice of each valve when brake is released.
Reservoir	Temporarily reserves the brake fluid drained from each brake, so that pressure efficiently decreases when decreasing pressure of each brake.
Pressure sensor	Detects the brake fluid pressure and transmits signal to ABS actuator and electric unit (control unit).

CONDITION FOR TURN ON THE WARNING LAMP

Turns ON when ignition switch ON and turns OFF when the system is normal, for bulb check purposes.

NOTE:

About electric parking brake warning lamp: Refer to System Description.

 

Condition (status)	ABS warning lamp	Brake warning lamp	VDC warning lamp
Ignition switch OFF (Auto ACC function OFF)	OFF	OFF	OFF
For approx. 1 second after the ignition switch is ON	ON	ON	ON
Approx. 1 second after ignition switch is ON (when the before engine starts, system is in normal operation)	OFF	ON	OFF
After engine starts	OFF	OFF	OFF
When brake fluid is less than the specified level (brake fluid level switch ON)	OFF	ON	ON
VDC function is malfunctioning	OFF	OFF	ON
TCS function is malfunctioning	OFF	OFF	ON
ABS function is malfunctioning	ON	OFF	ON
EBD function is malfunctioning	ON	ON	ON
Active brake limited slip (ABLS) function is malfunctioning	OFF	OFF	ON
Brake assist function is malfunctioning	OFF	OFF	ON
Brake force distribution function is malfunctioning	OFF	OFF	ON
hill start assist function is malfunctioning	OFF	OFF	ON
Brake vacuum sensor function is malfunctioning	OFF	ON	OFF
VDC function is operating	OFF	OFF	Blinking
TCS function is operating	OFF	OFF	Blinking
ABS function is operating	OFF	OFF	OFF
EBD function is operating	OFF	OFF	OFF
Active brake limited slip (ABLS) function is operating	OFF	OFF	Blinking
Brake assist function is operating	OFF	OFF	OFF
Brake force distribution function is operating	OFF	OFF	OFF
hill start assist function is operating	OFF	OFF	OFF

CONDITION FOR TURN ON THE INDICATOR LAMP

Turns ON when ignition switch is ON and turns OFF when the system is normal, for bulb check purposes.

NOTE:

About electric parking brake indicator lamp: Refer to System Description.

 

Condition (status)	VDC OFF indicator lamp
Ignition switch OFF (Auto ACC function OFF)	OFF
For approx. 1 second after the ignition switch is ON	ON
Approx. 1 second after ignition switch is ON (when system is in normal operation)	OFF
After engine starts (when system is in normal operation)	OFF
VDC setting is OFF (VDC OFF indicator is turn ON)	ON
VDC function is malfunctioning	OFF
TCS function is malfunctioning	OFF

Vdc Function System Description

• Side slip or tail slip may occur while driving on a slippery road or intending an urgent evasive driving. VDC function detects side slip status using each sensor when side slip or tail slip is about to occur and improves Nissan Pathfinder vehicle stability by brake control and engine output control during driving.

• In addition to TCS function, ABS function and EBD function, target side slip amount is calculated according to steering operation amount from steering angle sensor and brake operation amount from pressure sensor. By comparing this information with Nissan Pathfinder vehicle side slip amount that is calculated from information from yaw rate/side G sensor and wheel sensor, vehicle driving conditions (conditions of understeer or oversteer) are judged and Nissan Pathfinder vehicle stability is improved by brake force control on all 4 wheels and engine output control.

  

• VDC function can be switched to non-operational status (OFF). In this case, VDC OFF indicator lamp turns ON.

• Control unit portion automatically improves driving stability by performing brake force control as well as engine output control, by transmitting drive signal to actuator portion according to difference between target side slip amount and Nissan Pathfinder vehicle side slip amount.

• VDC warning lamp blinks while VDC function is in operation and indicates to the driver that the function is in operation.

• CONSULT can be used to diagnose the system diagnosis.

• Fail-safe function is adopted. When a malfunction occurs in VDC function, the control is suspended for VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. The Nissan Pathfinder vehicle status becomes the same as models without VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. However, ABS function and EBD function are operated normally. Refer to Fail-Safe.

  NOTE:

  VDC has the characteristic as described here, This is not the device that helps reckless driving.

   

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
ECM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Accelerator pedal position signal Engine speed signal Engine torque signal
TCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Current gear position signal AT accept permission signal Shift position signal
BCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Stop lamp switch signal Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication. Stop lamp request signal
IPDM E/R	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Ignition switch ON signal
Steering angle sensor	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Steering angle sensor signal
Combination meter	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Brake fluid level 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

OPERATION CHARACTERISTICS

VDC Function That Prevents Oversteer Tendency

• During a cornering, brake force (brake fluid pressure) is applied on front wheel and rear wheel on the outer side of turn. Moment directing towards the outer side of turn is generated. Oversteer is prevented.

  

• Changing driving lane on a slippery road, when oversteer tendency is judged large, engine output is controlled as well as brake force (brake fluid pressure) of 4 wheels. Oversteer tendency decreases.

  

VDC Function That Prevents Tendency

• During a cornering, brake force (brake fluid pressure) is applied on front wheel and rear wheel on the inner side of turn. Moment directing towards the inner side of turn is generated. Understeer is prevented.

  

• Applying braking during a cornering on a slippery road, when understeer tendency is judged large, engine output is controlled as well as brake force (brake fluid pressure) of four wheels. Understeer tendency decreases.

  

Tcs Function System Description

• Wheel spin status of drive wheel is detected by wheel sensor of 4 wheels. Engine output and transmission shift status is controlled so that slip rate of drive wheels is in appropriate level. When wheel spin occurs on drive wheel, ABS actuator and electric unit (control unit) perform brake force control of LH and RH drive wheels (apply brake force by increasing brake fluid pressure of drive wheel) and decrease engine torque by engine torque control. Wheel spin amount decreases. Engine torque is controlled to appropriate level.

  

• TCS function can be switched to non-operational status (OFF). In this case, VDC OFF indicator lamp turns ON.

• VDC warning lamp blinks while TCS function is in operation and indicates to the driver that the function is in operation.

• CONSULT can be used to diagnose the system diagnosis.

• Fail-safe function is adopted. When a malfunction occurs in TCS function, the control is suspended for VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. The Nissan Pathfinder vehicle status becomes the same as models without VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. However, ABS function and EBD function are operated normally. Refer to Fail-Safe.

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
ECM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Accelerator pedal position signal Engine speed signal Engine torque signal
TCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Current gear position signal AT accept permission signal Shift position signal
BCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Stop lamp switch signal Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication. Stop lamp request signal
IPDM E/R	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Ignition switch ON signal
Steering angle sensor	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Steering angle sensor signal
Combination meter	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Brake fluid level 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

Abs Function System Description

• By preventing wheel lock through brake force (brake fluid pressure) control that is electronically controlled by detecting wheel speed during braking, stability during emergency braking is improved so that obstacles can be easily bypassed by steering operation.

• During braking, control units calculates wheel speed and pseudo-Nissan Pathfinder vehicle speed, and transmits pressure increase, hold or decrease signals to actuator portion according to wheel slip status.

• The following effects are obtained by preventing wheel lock during braking.

  

  • Nissan Pathfinder Vehicle tail slip is prevented during braking when driving straight.

  • Understeer and oversteer tendencies are moderated during braking driving on a corner.

  • Obstacles may be easily bypassed by steering operation during braking.

• CONSULT can be used to diagnose the system diagnosis.

• Fail-safe function is adopted. When a malfunction occurs in ABS function, the control is suspended for VDC function, TCS function, ABS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. The Nissan Pathfinder vehicle status becomes the same as models without VDC function, TCS function, ABS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. However, EBD function is operated normally. Refer to Fail-Safe.

NOTE:

 

• ABS function has the characteristic as described here, This is not the device that helps reckless driving.

• To stop Nissan Pathfinder vehicle efficiently, ABS does not operate and ordinary brake operates at low speed [Approximately 6 MPH (10 km/h) or less, but differs subject to road conditions).

• Self-diagnosis is performed immediately after when engine starts and when Nissan Pathfinder vehicle initially is driven [by vehicle speed approximately 9 MPH (15 km/h)]. Motor sounds are generated during self-diagnosis. In addition, brake pedal may be felt heavy when depressing brake pedal lightly. These symptoms are not malfunctions.

 

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
Combination meter	Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication. VDC warning lamp signal ABS warning lamp signal
BCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Stop lamp switch signal

Ebd Function System Description

• By preventing rear wheel slip increase through rear wheel brake force (brake fluid pressure) control that is electronically controlled when slight skip on front and rear wheels are detected during braking, stability during braking is improved.

• EBD function is expanded and developed from conventional ABS function and corrects rear wheel brake force to appropriate level by electronic control according to load weight (number of passengers).

  

• During braking, control unit portion compares slight slip on front and rear wheels by wheel speed sensor signal, transmits drive signal to actuator portion when rear wheel slip exceeds front wheel slip for the specified value or more, and controls rear wheel brake force (brake fluid pressure) so that increase of rear wheel slip is prevented and slips on front wheel and rear wheel are nearly equalized. ABS control is applied when slip on each wheel increases and wheel speed is the threshold value of ABS control or less.

  

• CONSULT can be used to diagnose the system diagnosis.

• Fail-safe function is adopted. When a malfunction occurs in EBD function, the control is suspended for VDC function, TCS function, ABS function, EBD function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. The Nissan Pathfinder vehicle status becomes the same as models without VDC function, TCS function, ABS function, EBD function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. Refer to Fail-Safe.

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
Combination meter	Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication. VDC warning lamp signal ABS warning lamp signal Brake warning lamp signal
BCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Stop lamp switch signal

Active Brake Limited Slip (abls) Function System Description

• LH and RH driving wheel spin is always monitored. If necessary, appropriate brake force is independently applied to LH or RH driving wheel so that one-sided wheel spin is avoided and traction is maintained. Mainly starting ability is improved.

• Active brake limited slip (ABLS) function operates while VDC function is in non-operational status (OFF).

• VDC warning lamp blinking while active brake limited slip (ABLS) function is in operation and indicates to the driver that the function is in operation.

• Slight vibrations are felt on the brake pedal and the operation noises occur, when active brake limited slip (ABLS) function operates. This is not a malfunction because it is caused by active brake limited slip (ABLS) function that is normally operated.

• Fail-safe function is adopted. When a malfunction occurs in active brake limited slip (ABLS) function, the control is suspended for VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. The Nissan Pathfinder vehicle status becomes the same as models without VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. However, ABS function and EBD function are operated normally. Refer to Fail-Safe.

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
ECM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Accelerator pedal position signal Engine speed signal Engine torque signal
TCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Current gear position signal AT accept permission signal Shift position signal
BCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Stop lamp switch signal Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication. Stop lamp request signal
IPDM E/R	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Ignition switch ON signal
Steering angle sensor	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Steering angle sensor signal
Combination meter	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Brake fluid level 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

Brake Assist Function System Description

• When the driver brakes hard in an emergency, the stopping distance is reduced by increasing brake fluid pressure.

• Fail-safe function is adopted. When a malfunction occurs in brake assist function, the control is suspended for VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. The Nissan Pathfinder vehicle status becomes the same as models without VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. Refer to Fail-Safe.

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
ECM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Accelerator pedal position signal Engine speed signal Engine torque signal
TCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Current gear position signal AT accept permission signal Shift position signal
BCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Stop lamp switch signal Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication. Stop lamp request signal
IPDM E/R	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Ignition switch ON signal
Steering angle sensor	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Steering angle sensor signal
Combination meter	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Brake fluid level 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

Brake Force Distribution Function System Description

• Brake force distribution function helps provide a more stable and secure feeling.

  

• During cornering, when brake operation is performed brake fluid pressure of each wheel is controlled based on steering operation amount by the driver and Nissan Pathfinder vehicle cornering status amount detected by each sensor.

  

• Fail-safe function is adopted. When a malfunction occurs in brake force distribution function, the control is suspended for VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. The Nissan Pathfinder vehicle status becomes the same as models without VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. However ABS function and EBD function are operated normally. Refer to Fail-Safe.

NOTE:

Brake force distribution function may not always be operates in all driving conditions.

 

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
ECM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Accelerator pedal position signal Engine speed signal Engine torque signal
TCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Current gear position signal AT accept permission signal Shift position signal
BCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Stop lamp switch signal Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication. Stop lamp request signal
IPDM E/R	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Ignition switch ON signal
Steering angle sensor	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Steering angle sensor signal
Combination meter	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Brake fluid level 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

Hill Start Assist Function System Description

• This function maintains brake fluid pressure so that the vehicle does not move backwards even if brake pedal is released to depress accelerator pedal to start the Nissan Pathfinder vehicle while it is stopped on an uphill slope by depressing brake pedal.

• This function operates when the Nissan Pathfinder vehicle is in stop status on an uphill slope of slope ratio 10% or more and electric shift selector is in the position other than P or N.

• hill start assist function is only for the start aid. It maintains the brake fluid pressure for approximately 2 seconds after releasing the brake pedal, and then decreases the pressure gradually. If the Nissan Pathfinder vehicle can start by the accelerator operation, the brake is released automatically and a smooth start can be performed.

• Fail-safe function is adopted. When a malfunction occurs in hill start assist function, the control is suspended for VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. The Nissan Pathfinder vehicle status becomes the same as models without VDC function, TCS function, active brake limited slip (ABLS) function, brake assist function, brake force distribution function, and hill start assist function. Refer to Fail-Safe.

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
ECM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Accelerator pedal position signal Engine speed signal Engine torque signal
TCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Current gear position signal CVT accept permission signal Shift position signal
BCM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Stop lamp switch signal Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication. Stop lamp request signal
IPDM E/R	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Ignition switch ON signal
Steering angle sensor	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Steering angle sensor signal
Combination meter	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Brake fluid level 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

Intelligent Trace Control Function System Description

• Intelligent trace control function controls the braking utilizing the ABS actuator and electric unit (control unit), depending on cornering condition calculated from driver's steering input and plural sensors.

• Intelligent trace control function is aimed to enhance traceability at corners and smooth the Nissan Pathfinder vehicle movement to provide confident driving.

• When the VDC OFF display is used to turn OFF the VDC system, the intelligent trace control system is also turned OFF.

• When the intelligent trace control is operated, intelligent trace control graphics are shown on the information display of combination meter. These are shown only when “Chassis control” is selected on the information display. Refer to Chassis Control Warning.

• When the intelligent trace control is not functioning properly, the master warning lamp illuminates. Warning message “Chassis control” will also appear on information display.

NOTE:

• The intelligent trace control may not be effective depending on the driving condition. Always driving carefully and attentively.

• Brake pedal may vibrate and brake pedal feel may change during intelligent trace control operation. Also operation noise may be noticeable during operation. These are not abnormal conditions.

• When the intelligent trace control is selected OFF, some functions will be kept ON to assist driver. (For example, avoidance condition.)

 

OPERATION CHARACTERISTICS

Intelligent trace control helps enhance the transition from braking into and then accelerating out of corners. Intelligent trace control utilizes the Nissan Pathfinder vehicle′s electrically-driven intelligent brake system to help improve cornering feel by automatically applying brakes. Furthermore, Intelligent trace control will apply selective braking to help create increased steering response in S-turns. For example, if driving through an S-turn that starts with steering to the right, the right-side brakes are engaged to create a yaw momentum and help turn the Nissan Pathfinder vehicle.

• Brake control amount is controlled according to steering operation status by the driver and Nissan Pathfinder vehicle cornering status.

  

• During cornering, the brake control system limits changes in steering angle by controlling the inner ring brakes according to accelerator pedal operation and allows smooth movement of the Nissan Pathfinder vehicle to achieve stable cornering.

  

SYSTEM DIAGRAM

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
ECM	Mainly transmits the following signals to chassis control module via CAN communication. Accelerator pedal position signal Engine torque signal Engine speed signal
ABS actuator and electric unit (control unit)	Mainly transmits the following signals to chassis control module via CAN communication. Front LH wheel speed signal Front RH wheel speed signal Rear LH wheel speed signal Rear RH wheel speed signal ABS operation signal TCS operation signal VDC operation signal Stop lamp switch signal Nissan Pathfinder Vehicle speed signal (ABS) Yaw rate signal Side G signal Decel G signal VDC OFF switch signal Brake fluid pressure signal Steering angle sensor signal Mainly receives the following signals from chassis control module via CAN communication. Intelligent trace control signal
Steering angle sensor	Mainly transmits the following signals to chassis control module via CAN communication. Steering angle sensor signal
Chassis control module	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication. Intelligent trace control signal Drive mode signal
Integral switch	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication line. Intelligent trace control operation signal
Combination meter	Mainly receives the following signals from chassis control module via CAN communication. Chassis control malfunction signal Intelligent trace control display signal

Warning/indicator/chime List Warning Lamp/Indicator Lamp

FOR USA

Name	Design	Layout/Function
ABS warning lamp		For layout 7 inch information display: Refer to Design.
		For function 7 inch information display: Refer to Component Function Check.
VDC warning lamp		For layout 7 inch information display: Refer to Design.
		For function 7 inch information display: Refer to Component Function Check.
Brake warning lamp		For layout 7 inch information display: Refer to Design.
		For function 7 inch information display: Refer to Component Function Check.
VDC OFF indicator lamp		For layout 7 inch information display: Refer to Design.
		For function 7 inch information display: Refer to Component Function Check.
Electric parking brake indicator lamp		For layout 7 inch information display: Refer to Design.
		For function 7 inch information display: Refer to Component Function Check.
Electric parking brake warning lamp		For layout 7 inch information display: Refer to Design.
		For function 7 inch information display: Refer to Component Function Check.

EXCEPT FOR USA

Name	Design	Layout/Function
ABS warning lamp		For layout: Refer to Design.
		For function: Refer to Component Function Check.
VDC warning lamp		For layout: Refer to Design.
		For function: Refer to Component Function Check.
Brake warning lamp		For layout: Refer to Design.
		For function: fer to Component Function Check.
VDC OFF indicator lamp		For layout: Refer to Design.
		For function: refer to Component Function Check.
Electric parking brake indicator lamp		For layout: Refer to Design.
		For function: Refer to Component Function Check.
Electric parking brake warning lamp		For layout: Refer to Design.
		For function: Refer to Component Function Check.

Handling Precaution Drive Mode Selector

VDC FUNCTION CHARACTERISTICS

• The VDC function characteristics when a mode is switched with the drive mode select switch is as follows.

  Drive mode select switch	VDC function status
  STANDARD/AUTO	Normal.
  SAND	The optimal driving torque is distributed according to the driving mode selected.
  MUD/RUT	The optimal driving torque is distributed according to the driving mode selected.
  SNOW	The optimal driving torque is distributed according to the driving mode selected.