Traction control is capable of two things - cutting power and applying braking. In my experience, it is quite apparent when it engages and it will not engage unless there is a pretty severe loss of traction. There is a grinding sound like when antilock brakes engage and/or there is a drastic cut in power. From the manual:
PRINCIPLES OF OPERATION The traction control system helps avoid drive wheel spin and loss of traction. If your vehicle begins to slide, the system applies the brakes to individual wheels and, when needed, reduces engine power at the same time. If the wheels spin when accelerating on slippery or loose surfaces, the system reduces engine power in order to increase traction. USING TRACTION CONTROL Note: If your vehicle is equipped with MyKey®, it is possible to prevent turning the traction control system off. See the MyKey chapter. In certain situations (for example, stuck in snow or mud), turning the traction control off may be beneficial as this allows the wheels to spin with full engine power. Turn the traction control system off by pressing the stability control button located in the access door under the climate controls on Taurus SHO models, or through the information display on other models.
