Nissan Quest E52. Manual - part 231

SYSTEM

BRC-17

< SYSTEM DESCRIPTION >

[WITH VDC]

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The following descriptions explains the control of front brake right side, as an example.

Under Normal Brake Operation

Since power is not supplied to the ABS IN valve and the ABS OUT valve, the ABS IN valve port is open and
the ABS OUT valve port is closed. This allows the master cylinder fluid pressure to be sent to the front RH cal-
iper and blocks the brake fluid passage to the reservoir.

When Pressure Increases

The control unit pressurizes the inside of the brake caliper by opening the ABS IN valve port and closing the
ABS OUT valve port. After breaking the circuit, the valves operate in the same way as described in “Under
Normal Brake Operation.” The fluid amount supplied from the master cylinder to the brake caliper is controlled,
according to the power supply cut-off time (time to open the port) to the ABS IN valve.

When Pressure Holds

JSFIA0969GB

BRC-18

< SYSTEM DESCRIPTION >

[WITH VDC]

SYSTEM

The control unit passes an electric current to the ABS IN valve and closes the ABS IN valve port. Since power
is not supplied to the ABS OUT valve, its port is closed. The paths to the brake caliper, master cylinder, and
reservoir are cut off. This allows the front RH caliper fluid pressure to be maintained.

When Pressure Decreases

The control unit closes the ABS IN valve port and opens the ABS OUT valve port by supplying power to the
ABS IN valve and the ABS OUT valve. The brake fluid of the front RH caliper passes through the ABS OUT
valve to the reservoir and stays in the reservoir. After this the brake fluid is pumped up to return to the master
cylinder.

When brake released

The fluid pressure returns from the front RH caliper to the master cylinder through the return check valve
opened by the ABS IN valve port and fluid pressure.

Component Parts and Function

CONDITION FOR TURN ON THE WARNING LAMP

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

CONDITION FOR TURN ON THE INDICATOR LAMP

Component

Function

Pump

Feeds brake fluid by the motor.

Motor

Activates the pump 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.

ABS OUT valve

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

Cut valve 1
Cut valve 2

Shuts off the ordinary brake line from master cylinder, when VDC function, TCS function and brake 
limited slip differential (BLSD) function are activated.

Suction valve 1
Suction valve 2

Supplies the brake fluid from master cylinder to the pump, when VDC function, TCS function and 
brake limited slip differential (BLSD) function are activated.

Inlet valve

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

Outlet valve

Brake fluid discharged from the pump does not backflow.

Return check valve

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

Pressure sensor

Detects the brake fluid pressure and transmits signal to control unit.

Reservoir

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

Damper

Reduces the vibrations travelling to the brake pedal during the operation of the VDC function, TCS 
function, ABS function, EBD function, or brake limited slip differential (BLSD) function.

Condition (status)

ABS warning lamp

Brake warning lamp

VDC warning lamp

Ignition switch OFF

OFF

OFF

OFF

For approx. 2 seconds after the ignition switch is turned ON

ON

ON

ON

Approx. 2 seconds after ignition switch is turned ON (when the sys-
tem is in normal operation)

OFF

OFF

OFF

When parking brake operates (parking brake switch ON)

OFF

ON

OFF

When brake fluid is less than the specified level (brake fluid level 
switch ON)

OFF

ON

OFF

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

Brake limited slip differential (BLSD) function is malfunctioning

OFF

OFF

ON

VDC function is operating

OFF

OFF

Blinking

TCS function is operating

OFF

OFF

Blinking

SYSTEM

BRC-19

< SYSTEM DESCRIPTION >

[WITH VDC]

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• Turns ON when VDC function and TCS function are switched to non-operational status (OFF) by VDC OFF

switch.

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

Condition (status)

VDC OFF indicator lamp

Ignition switch OFF

OFF

For approx. 2 seconds after the ignition switch is turned ON

ON

Approx. 2 seconds after ignition switch is turned ON (when the sys-
tem is in normal operation)

OFF

When VDC OFF switch is ON (VDC function and TCS function are 
OFF)

ON

BRC-20

< SYSTEM DESCRIPTION >

[WITH VDC]

SYSTEM

Circuit Diagram

INFOID:0000000009651358

Fail-safe

INFOID:0000000009651359

VDC FUNCTION, TCS FUNCTION AND BRAKE LIMITED SLIP DIFFERENTIAL (BLSD) FUNCTION

VDC warning lamp in combination meter turn ON when a malfunction occurs in system [ABS actuator and
electric unit (control unit)]. The control is suspended for VDC function, TCS function and brake limited slip dif-

JSFIA0970GB