2004 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 230

SERVICE BRAKE BOOSTER If your vehicle has vaccum assist power brakes, this message will be displayed on the DIC when there is a problem with the Supplemental Brake Assist system. If the message is displayed immediately after starting the vehicle or the message appears while driving, your Supplemental Brake Assist system needs service. See Brake System Warning Light on page 3-44. CAUTION: (Continued) pedal will be harder to push and it will take longer to stop. If you continue to drive with this message displayed it can lead to a crash. Have the brake system serviced as soon as possible. {CAUTION: Your brake system may not be working properly if the SERVICE BRAKE BOOSTER message is displayed. If the brake system warning light is also on, you should have the vehicle towed for service. See "Brake System Warning Light" in the Index. If the brake system warning light isn't on, you still have brakes, but the supplemental brake assist system may not operate properly. In the event of a vacuum loss, you may not have vacuum power assist for braking. The brake CAUTION: (Continued) SERVICE 4 WHEEL STEER If a problem occurs with the 4 wheel steer system, this message will appear on the DIC. If this message appears, stop as soon as possible, and turn off the vehicle. Restart the vehicle and check for the message on the DIC display. If the message is still displayed, or appears again when you being driving, the four wheel steer system needs service. SERVICE 4WD If a problem occurs with the four wheel drive system, this message will appear on the DIC. If this message appears, stop as soon as possible and turn off the vehicle. Restart the vehicle and check for the message on the DIC display. If the message is still displayed, or appears again when you begin driving, the four wheel drive system needs service. 3-70