i have a 2004 gmc sierra with 150k miles . the service brake booster lite came on 2 days ago when i started the truck and has not came on since. i dont hear any scraping or the screamers on the brakes . my brake pedal is not sinking. it has been a great truck, but i have always had minor elactrical issues and wondering if this is another one. i dont know much about vehicles other than basics and havent found anyone that can give me advice. i hate to take and not be able to talk intellgently with mechanic. i am in a new town and dont have a regular mechanic that i can trust. thanks for any input.
First, I would check to see what the owner’s manual has to say about it. You should also check your brake fluid level either way.
Does it specifically say brake booster? The brake booster is right there in front of your brake pedal on the firewall. It looks like a big black canister. If it has a problem it won’t be down at the wheels making noise. It uses vacuum from the engine to help apply the brakes. Have you noticed anything strange in the brake pedal? Has the engine started to stumble at all when you apply the brakes?
In any case, if the light is now off and nothing about the brakes has changed then I would not worry about it for now (other than checking the brake fluid and owner’s manual). Worry if it comes back on and stays on.
Do you have Electronic braking assist? If so, it may be a warning about the solenoid that triggers it. (The purpose of the system is to help you apply full brakes quicker in an emergency.)
Here is some information from ALLDATA…
The SERVICE BRAKE BOOSTER message will be displayed when the supplemental brake assist signal circuit is toggled at 1.0 Hz with a 50 percent duty cycle. This message is also displayed if the instrument panel cluster (IPC) does not see an alive and well signal at key on. When this message is displayed it indicates a problem with the SBA and should be serviced or replaced.
This is a RECALL on the hydroboost system, I don’t know if it applies to your vehicle so you would have to contact a GMC dealer to see if the recall applies to your truck.
General Motors has decided that a defect, which relates to motor vehicle safety, exists in certain 2004 Chevrolet Kodiak and GMC TopKick; 2004-2005 Chevrolet Avalanche, Express, Silverado, Suburban; GMC Savana, Sierra, Yukon XL vehicles. On some of these vehicles, the hydraulic brake booster’s pressure accumulator may crack and/or separate from the Hydro-Boost® assembly during normal vehicle operating conditions. If a separation were to occur and the hood of the vehicle were open, fragments from the accumulator could cause injury to people in the immediate area. In addition, the presence of this crack or fractured surface could allow the hydraulic fluid to leak from the accumulator circuit of the booster assembly. The loss of fluid would cause increased steering and braking effort.
the brake pedal has been fine. i will check the fluid. thank you for your input