Toyota Tundra. Manual — part 911

Fig. 11: Identifying Traction Control - System Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. Operation description

The skid control ECU detects the vehicle's slip condition by receiving signals from each
speed sensor and the ECM via CAN communication. The skid control ECU controls engine
torque with the ECM via CAN communication and brake fluid pressure through the pump
and solenoid valve. The SLIP indicator light blinks when the system is operating. The VSC
OFF indicator light blinks and the SLIP indicator light comes on when the TRAC system
malfunctions.

f. VSC (Vehicle Stability Control) (for 2WD vehicles or 4WD vehicles in 2WD mode)

The VSC system helps prevent the vehicle from slipping sideways when front or rear wheel
skidding occurs while cornering.

2009 Toyota Tundra

2009 BRAKES Brake Control - Tundra

Fig. 12: Identifying Vehicle Stability Control - System Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. Operation description

The skid control ECU determines the vehicle condition by receiving signals from the speed
sensor, yaw rate and deceleration sensor and steering angle sensor. The skid control ECU
controls driving torque with the ECM via CAN communication, and brake fluid pressure
with the solenoid valve.

The SLIP indicator light blinks and the skid control buzzer sounds when the system is
operating. When there is a malfunction in the VSC system, the VSC OFF indicator light
blinks and the SLIP indicator light comes on. The VSC OFF switch stops VSC operation.

g. A-TRAC (Active Traction Control) (for 4WD)

During rugged off-road driving, this function controls the engine output and the brake fluid

2009 Toyota Tundra

2009 BRAKES Brake Control - Tundra

pressure that is applied to the slipping wheel and distributes the drive force that would have been
lost through the slippage to the remaining wheels in order to achieve an LSD (Limited Slip
Differential) effect.

HINT:

The A-TRAC system operates when the 4WD control switch is set to 4L or 4H (4WD vehicles
only).

Fig. 13: Identifying Active Traction Control - System Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. Operation description

The SLIP indicator light blinks when the system is operating. The VSC OFF indicator light
blinks and the SLIP indicator light comes on to indicate a malfunction in the A-TRAC
system.

h. AUTO LSD (Auto Limited Slip Differential) For 2WD vehicles and 4WD vehicles in 2H mode, the

AUTO LSD will operate with the VSC OFF switch on (approximately 1 second) and the
accelerator pedal depressed.

2009 Toyota Tundra

2009 BRAKES Brake Control - Tundra

The AUTO LSD system is used to restrain brake pressure and reduce differential movement, thus
transmitting drive torque to the other drive wheel to ensure startability under the following
conditions:



Wheels run off the road.



Drive wheels slip when starting on a slope with one wheel on snow/ice.

HINT:

Depressing the brake pedal cancels control of the AUTO LSD system.

Fig. 14: Identifying AUTO LSD - System Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. Operation description

The SLIP indicator light blinks and the AUTO LSD indicator light comes on when the

2009 Toyota Tundra

2009 BRAKES Brake Control - Tundra