2009 Toyota 4Runner Owners Manual - Page 220

2-4. Using other driving systems n Sounds and vibrations caused by the ABS, TRAC, A-TRAC, VSC and brake assist system l A sound may be heard from the engine compartment when the engine is started or just after the vehicle begins to move. This sound does not indicate that a malfunction has occurred in any of these systems. l Any of the following conditions may occur when the above systems are operating. None of these indicates that a malfunction has occurred Vibrations may be felt through the vehicle body and steering. A motor sound may be heard after the vehicle comes to a stop. The brake pedal may pulsate slightly after the ABS is activated. The brake pedal may move down slightly after the ABS is activated. n If the brake system overheats TRAC will cease operation and a buzzer will sound to alert the driver. Stop the vehicle in a safe place. (There is no problem with continuing normal driving.) 196