From the owner's manual:
TRACTION CONTROL (IF EQUIPPED)
During Traction Control operation, the traction control active light will illuminate, you may hear an electric motor type of sound coming from the engine compartment and the engine will not “rev-up” when you push further on the accelerator. This is normal system behavior and should be no reason for concern.
At speeds below 85 km/h (53 mph), both the engine and the brake
system will be used to control wheel spin; at speeds above 85 km/h (53
mph), only engine torque reduction is used. When the Traction Control
system is switched off, the braking system will still be used to control
wheel spin at speeds below 40 km/h (25 mph).
If a system fault is detected, the traction control active light will
illuminate, the Traction Control button will not turn the system on or
off and your vehicle should be serviced.
2004 Focus