The TL features Electronic Brake Force Distribution (EBD), which continuously and automatically adjusts the pressure distribution between the front and rear brakes depending on how the vehicle is dynamically loaded.
Brake Assist
Brake Assist comes standard on the TL. Its purpose is to help the driver apply full braking pressure in a "panic stop" situation. To do so, a microprocessor continually analyzes and "learns" the driver's normal braking habits.
In an emergency braking situation when the brakes are suddenly applied and partially released by the driver to avoid wheel lockup, brake assist helps the driver apply full braking force via the anti-lock actuator. A pressure sensor detects an increase in brake fluid pressure and activates the anti-lock braking system. Braking pressure is maintained momentarily after the driver's initial braking action unless the driver completely releases the brake pedal.
Anti-lock Braking System
Standard on the TL is a three-channel Anti-lock Braking System (ABS), which works in conjunction with the Vehicle Stability Assist™ (VSA®) system. Utilizing speed sensors located at each wheel, the system modulates braking power to the front wheels independently and to the rear wheels in tandem-enhancing driver control during maximum-effort stops. For 2007, a new ABS modulator improves response time and reduces noise when operating.
VEHICLE STABILITY ASSIST™ (VSA®)
The TL is equipped with 4-channel Vehicle Stability Assist™ (VSA®) that helps the driver retain control of the car in the event the vehicle reaches its dynamic traction limits. For example, this may occur through aggressive cornering, encountering ice or dirt on the road, or entering a decreasing-radius corner too fast.
In the event of understeer, the system can apply the inside front and rear brakes to increase yaw, slowing the vehicle and enabling it to complete the turn. Engine torque may also be reduced by coordination of the Drive-by-Wire Throttle System™ and powertrain control module.
The 4-channel system controls all four brakes independently. In the event of oversteer (where the rear tires lose grip), the system can apply the outside front and rear brakes to decrease yaw, slowing the vehicle and enabling it to stay on its intended path.
An indicator light on the instrument panel alerts the driver whenever the VSA system is actively enhancing the vehicle's stability.
The traction control component of VSA uses sensors that monitor each of the wheels and a computer-controlled modulation of engine power and front brakes to help prevent wheel spin when starting out or accelerating. If the sensors detect wheel spin, traction control reduces engine power and applies brake force to the affected wheels. This helps the TL maintain traction during acceleration and helps the driver retain steering control, even when accelerating on slippery surfaces.
A cockpit switch is provided to disable the vehicle stability and traction control aspects of the system while leaving the ABS system fully functional.