2003 Toyota 4Runner Owners Manual - Page 977

'03 4Runner_U (L/O 0301) Iridium-tipped spark plugs (2UZ-FE engine) Brake system This brake system has 2 independent hydraulic circuits. If either circuit should fail, the other will still work. However, the pedal will be harder to press, and your stopping distance will be longer. Also, the brake system warning light may come on. Depressing the brake pedal repeatedly may turn on the brake system warning light and buzzer. It is normal if the light turns off and the buzzer stops sounding after a few seconds. You may hear a small sound in the engine compartment after the engine is started or the brake pedal is depressed repeatedly. This is a pump pulsating sound of the brake system, and it is not a malfunction. CAUTION Do not drive your vehicle with only a single brake system. Have your brakes fixed immediately. BRAKE BOOSTER The brake booster uses brake fluid pressurized by the pump to power-assist the brakes. If the brake booster fails during driving, the brake system warning light comes on and buzzer sounds continuously. In this case, the brakes may not work properly. If they do not work well, depress the brake pedal firmly. If the brake system warning light comes on, immediately stop your vehicle and contact your Toyota dealer. It is not a malfunction that the brake system warning light may stay on for 60 seconds after the ignition key is turned to the "ON" position. CAUTION Your engine is fitted with iridium-tipped spark plugs. D Do not pump the brake pedal if the engine stalls. Each push on the pedal uses up your brake fluid pressure reserve. NOTICE Use only iridium-tipped spark plugs and do not adjust gaps for your engine performance and smooth driveability. 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 be longer. 247 2003 4RUNNER from JAN. '03 Prod. (OM35806U)