System Description
- The system switches fluid pressure of each brake caliper 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, hill start assist function, brake limited slip differential (BLSD) function and trailer sway control function.
- Fail-safe function is available for each function and is activated by each function when system malfunction occurs.
- The adoption of the 4WD switch assembly (4WD shift switch and VDC OFF switch) enables to change the control characteristics of the VDC function, the TCS function and the brake limited slip differential (BLSD) function into an optimal characteristics, based on a state of the 4WD shift switch. (Models with 4WD system)
SYSTEM DIAGRAM
NOTE:
Transfer control unit is applied to models with 4WD system.
INPUT SIGNAL AND OUTPUT SIGNAL
Major signal transmission between each unit via communication lines is shown in the following table.
| Component | Signal description |
|---|---|
| Yaw rate/side/decel G sensor | Mainly transmits the following signals to ABS actuator and electric unit (control unit) via communication line *1.
|
| ECM | Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication.
Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication.
|
| TCM | Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication.
|
| Transfer control unit *2 | Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication.
|
| Steering angle sensor | Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication.
|
| Combination meter | Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication.
|
*1: Communication line between yaw rate/side/decal G sensor and ABS actuator and electric unit (control unit)
*2: Models with 4WD system
VALVE OPERATION
Each valve is operated and fluid pressure of brake caliper is controlled.
When Ordinary Brake is Applied
NOTE:
Control pressure sensor is applied to models with Advanced Driver Assistance System.
| Name | Not activated | When depressing brake pedal |
|---|---|---|
| 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 caliper (fluid pressure) | - | Pressure increases |
Front RH caliper
- Pressurized brake fluid from accumulator is supplied to front RH caliper through master cylinder part, cut valve 1 and ABS IN valve.
Front LH caliper
- Pressurized brake fluid from accumulator is supplied to front LH caliper through master cylinder part, cut valve 1 and ABS IN valve.
Rear RH caliper
- Pressurized brake fluid from accumulator is supplied to rear RH caliper through master cylinder part, cut valve 2 and ABS IN valve.
Rear LH caliper
- Pressurized brake fluid from accumulator is supplied to rear LH caliper through master cylinder part, cut valve 2 and ABS IN valve.
ABS is Operation (When Pressure Increases)
NOTE:
Control pressure sensor is applied to models with Advanced Driver Assistance System.
| Name | 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 not supplied (open) |
| 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 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 caliper (fluid pressure) | - | Pressure increases |
Front RH caliper
- Pressurized brake fluid from accumulator is supplied to front RH caliper through master cylinder part, cut valve 2, suction valve 1 and ABS IN valve.
Front LH caliper
- Pressurized brake fluid from accumulator is supplied to front LH caliper through master cylinder part, cut valve 2, suction valve 1 and ABS IN valve.
Rear RH caliper
- Pressurized brake fluid from accumulator is supplied to rear RH caliper through master cylinder part, cut valve 2 and ABS IN valve.
Rear LH caliper
- Pressurized brake fluid from accumulator is supplied to rear LH caliper through master cylinder part, cut valve 2 and ABS IN valve.
ABS is Operation (When Pressure Holds)
NOTE:
Control pressure sensor is applied to models with Advanced Driver Assistance System.
| Name | 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 not supplied (open) |
| 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 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 caliper (fluid pressure) | - | Pressure holds |
Front RH caliper
- ABS IN valve is close, fluid pressure of front RH caliper is holds.
Front LH caliper
- ABS IN valve is close, fluid pressure of front LH caliper is holds.
Rear RH caliper
- ABS IN valve is close and fluid pressure of rear RH caliper is holds.
Rear LH caliper
- ABS IN valve is close and fluid pressure of rear LH caliper is holds.
ABS is Operation (When Pressure Decreases)
NOTE:
Control pressure sensor is applied to models with Advanced Driver Assistance System.
| Name | Not activated | When pressure decreases |
|---|---|---|
| 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 not supplied (open) |
| 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 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 caliper (fluid pressure) | - | Pressure decreases |
Front RH caliper
- Being returned to reservoir tank through ABS OUT valve, fluid pressure of front RH caliper is decreased.
Front LH caliper
- Being returned to reservoir tank through ABS OUT valve, fluid pressure of front LH caliper is decreased.
Rear RH caliper
- Being returned to reservoir tank through ABS OUT valve, fluid pressure of rear RH caliper is decreased.
Rear LH caliper
- Being returned to reservoir tank through ABS OUT valve, fluid pressure of rear LH caliper is decreased.
VDC is Operation (When Pressure Increases)
NOTE:
Control pressure sensor is applied to models with Advanced Driver Assistance System.
Example: When other than rear LH wheel is operation in the figure.
| Name | 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) | Only wheel that the pressure is to be increased: Power supply is not supplied (open) Wheel other than the one that the pressure is to be increased: Power supply is supplied (close) |
| ABS OUT valve | Power supply is not supplied (close) | Power supply is not supplied (close) |
| Each caliper (fluid pressure) | - | Pressure increases (only wheel that the pressure is to be increased) |
Front RH caliper
- Pressurized brake fluid from accumulator is supplied to front RH caliper through suction valve 2, suction valve 1 and ABS IN valve. When not increases, ABS IN valve is closed and brakes fluid is not supplied to front RH caliper.
Front LH caliper
- Pressurized brake fluid from accumulator is supplied to front LH caliper through suction valve 2, suction valve 1 and ABS IN valve. When not increases, ABS IN valve is closed and brakes fluid is not supplied to front LH caliper.
Rear RH caliper
- Pressurized brake fluid from accumulator is supplied to rear RH caliper through suction valve 2 and ABS IN valve. When not increases, ABS IN valve is closed and brakes fluid is not supplied to rear RH caliper.
Rear LH caliper
- Pressurized brake fluid from accumulator is supplied to rear LH caliper through suction valve 2 and ABS IN valve. When not increases, ABS IN valve is closed and brakes fluid is not supplied to rear LH caliper.
VDC is Operation (When Pressure Holds)
NOTE:
Control pressure sensor is applied to models with Advanced Driver Assistance System.
Example: When other than front LH wheel is operation in the figure.
| Name | 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 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) | Only wheel that the pressure is to be holds: Power supply is supplied (close) Wheel other than the one that the pressure is to be holds: Power supply is not supplied (open) |
| ABS OUT valve | Power supply is not supplied (close) | Power supply is not supplied (close) |
| Each caliper (fluid pressure) | - | Pressure holds (only wheel that the pressure is to be holds) |
Front RH caliper
- ABS IN valve is close, fluid pressure of front RH caliper is holds.
Front LH caliper
- ABS IN valve is close, fluid pressure of front LH caliper is holds.
Rear RH caliper
- ABS IN valve is close, fluid pressure of rear RH caliper is holds.
Rear LH caliper
- ABS IN valve is close, fluid pressure of rear LH caliper is holds.
VDC is Operation (When Pressure Decreases)
NOTE:
Control pressure sensor is applied to models with Advanced Driver Assistance System.
Example: When other than front LH wheel is operation in the figure.
| Name | Not activated | When pressure decreases |
|---|---|---|
| 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) | Only wheel that the pressure is to be decreases: Power supply is supplied (close) Wheel other than the one that the pressure is to be decreases: Power supply is not supplied (open) |
| ABS OUT valve | Power supply is not supplied (close) | Only wheel that the pressure is to be decreases: Power supply is supplied (open) Wheel other than the one that the pressure is to be decreases: Power supply is not supplied (close) |
| Each caliper (fluid pressure) | - | Pressure decreases (only wheel that the pressure is to be decreases) |
Front RH caliper
- Being returned to reservoir tank through ABS OUT valve, fluid pressure of front RH caliper is decreased.
Front LH caliper
- Being returned to reservoir tank through ABS OUT valve, fluid pressure of front LH caliper is decreased.
Rear RH caliper
- Being returned to reservoir tank through ABS OUT valve, fluid pressure of rear RH caliper is decreased.
Rear LH caliper
- Being returned to reservoir tank through ABS OUT valve, fluid pressure of rear LH caliper is decreased.
Component Parts and Function
| Component | Function |
|---|---|
| Pump | Operates the pump drive according to signals from ABS actuator and electric unit (control unit) by the motor. |
| Motor | Operates the motor drive according to signals from ABS actuator and electric unit (control unit). |
| Accumulator | The accumulator accumulates brake fluid conveyed by the motor and pump. |
| ABS IN valve | Increases, holds or decreases the fluid pressure of each caliper according to signals from ABS actuator and electric unit (control unit). |
| ABS OUT valve | Increases, holds or decreases the fluid pressure of each caliper 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 to signals from ABS actuator and electric unit (control unit). |
| Suction valve 1 | Suction Valve 1 switches the brake line to convey accumulator pressure to the front system, according to a signal transmitted from the ABS actuator and electric unit (control unit). |
| Suction valve 2 | Suction valve 2 releases accumulator pressure, according to a signal transmitted from the ABS actuator and electric unit (control unit). |
| Control pressure sensor * | Detects the brake fluid pressure of rear brake caliper and transmits a signal to ABS actuator and electric unit (control unit). |
| Accumulator pressure sensor | The accumulator pressure sensor detects brake fluid pressure accumulated in the accumulator and conveys the detected result to the ABS actuator and electric unit (control unit). |
| Master cylinder pressure sensor | Detects the brake fluid pressure of master cylinder part and transmits a signal to ABS actuator and electric unit (control unit). |
*: Models with Advanced Driver Assistance System
CONDITION FOR TURN ON THE WARNING LAMP
ABS Warning Lamp
- Turns ON at the same time as VDC warning lamp when either ABS function or EBD function is malfunctioning.
- Turns ON when ignition switch turns ON and turns OFF when the system is normal, for bulb check purposes.
| Condition (status) | ABS warning lamp |
|---|---|
| Ignition switch OFF | OFF |
| For approx. 1 second after the ignition switch is turned ON | ON |
| Approx. 1 second after ignition switch is turned ON (when the system is in normal operation) | OFF |
| ABS function is malfunctioning | ON |
| EBD function is malfunctioning | ON |
Brake Warning Lamp
- Turns ON at the same time as ABS warning lamp and VDC warning lamp when EBD function, motor/accumulator assembly or motor system is malfunctioning.
- Turns ON when ignition switch turns ON and turns OFF when the system is normal, for bulb check purposes.
| Condition (status) | Brake warning lamp |
|---|---|
| Ignition switch OFF | OFF |
| For approx. 1 second after the ignition switch is turned ON | ON |
| Approx. 1 second after ignition switch is turned ON (when the system is in normal operation) | OFF |
| After engine starts | OFF |
| When parking brake operates (parking brake switch ON) | ON |
| When brake fluid is less than the specified level (brake fluid level switch ON) | ON |
| ABS function is malfunctioning | OFF |
| EBD function is malfunctioning | ON |
| Accumulator is low pressure | ON |
| Motor system is malfunctioning | ON |
| Ignition power supply system is malfunctioning | ON |
VDC Warning Lamp
- Turns ON when either VDC function, TCS function, ABS function or EBD function, hill start assist function or brake limited slip differential (BLSD) function is malfunctioning.
- Turns ON when ignition switch turns ON and turns OFF when the system is normal, for bulb check purposes.
| Condition (status) | VDC warning lamp |
|---|---|
| Ignition switch OFF | OFF |
| For approx. 1 second after the ignition switch is turned ON | ON |
| Approx. 1 second after ignition switch is turned ON (when the system is in normal operation) | OFF |
| VDC function is malfunctioning | ON |
| TCS function is malfunctioning | ON |
| ABS function is malfunctioning | ON |
| EBD function is malfunctioning | ON |
| hill start assist function is malfunctioning | ON |
| Brake limited slip differential (BLSD) function is malfunctioning | ON |
| Trailer sway control function is malfunctioning | ON |
| VDC function is operating | Blinking |
| TCS function is operating | Blinking |
| Trailer sway control function is operating | Blinking |
CONDITION FOR TURN ON THE INDICATOR LAMP
VDC OFF Indicator Lamp
- 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. 1 second after the ignition switch is turned ON | ON |
| Approx. 1 second after ignition switch is turned ON (when the system is in normal operation) | OFF |
| When VDC OFF switch is ON (VDC function, TCS function and trailer sway control function are OFF) | ON |
| 4WD mode: 4L * | ON |
*: Models with 4WD system