2005 Lexus LS 430 Owners Manual - Page 406

STARTING AND DRIVING "Check VSC" warning message BRAKE SYSTEM The tandem master cylinder brake system is a hydraulic system with two separate sub−systems. If either sub−system should fail, the other will still work. However, the pedal will be harder to press, and your stopping distance will increase. Also, the brake system warning light may come on. 31L337a CAUTION Do not drive your vehicle with only a single brake system. Have your brakes fixed immediately. If the vehicle stability control system or the traction control system malfunctions, the master warning light and "TRAC OFF" indicator light come on. At this time a warning tone sounds and the above message appears. If the message appears, the vehicle stability control system and traction control system do not work. Although it is no problem to continue driving, have your vehicle checked by your Lexus dealer as soon as possible. Brake booster The brake booster uses engine vacuum to power−assist the brakes. If the engine should quit while you are driving, you can bring the vehicle to a stop with normal pedal pressure. There is enough reserved vacuum for one or two stops but no more! CAUTION D Do not pump the brake pedal if the engine stalls. Each push on the pedal uses up your reserved vacuum. D Even if the power assist is completely lost, the brakes will still work. But you will have to push the pedal hard, much harder than normal. And your braking distance will increase. 367