CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Brake Warning light/Service Brake System in info center

I have a 2008 Silverado 1500 WT. Over the past month or so (before Christmas), my brake light comes on after first starting the vehicle and shortly after driving for the first time of the day. The service brake system in the info center also comes on with the beeping warning. After a few seconds, about 30 or less, the lights all go off. As time went on, the lights started to come on and go off a few miles into the first trip of the day and started to do it twice. The lights come on but go off and nothing seems to be wrong. I have checked the pads/shoes and they are fine. I have also checked the brake fluid. All are fine. At times, the lights/warning indicators come on and go off repeatedly, and then clear. I have checked to make sure the E-Brake isn’t set or pushed down to set it off. Any ideas of what is causing this to happen? It is becoming annoying and possible dangerous if there is some mechanical problem with the brakes I am overlooking.

Check the brake fluid level sensor. If that is not it I would spare no time fixing whatever it is. Many times it is nothing dangerous, but if it is you can be putting many at risk. I’m not a freak on safety, but I could not drive a car with brake warnings until it is fixed, no matter whats causing the warning.

Have the error codes read. Not the engine codes, ABS codes. I’d guess there is an ABS error code at startup that is working itself out somehow.

1 Like

My scan tool pulled an error code U0073, which if I read write from here: U0073 – Control module – data bus Off – TroubleCodes.net, could be that the ECM and the ABS can’t communicate and have a possible short?

Yes. Because the problem is intermittant, I’d bet the data bus line has a break or short in it. Especially if there are no other ABS codes.

There is a TSB on this for your truck, I think. Might wanna look that up.

1 Like

Turns out my problem was low brake fluid levels. The reservoir was stained making it look full. Popped the cap and low and behold, it was low. I did a quick search and was not able to find the TBS you were referring to.

2 Likes

If a vehicle is maintained properly, if your fluid drops like that it indicates pad wear. Just to be cautious, I would have all pads checked for wear.

3 Likes

just curious, when was it last time the brake fluid was replaced and what the maintenance schedule says about it?

I checked the pads and shoes, all were fine if not almost new.

I don’t mean to be a nag, but it now concerns me why the fluid was low. The 2 biggest reasons that fluid level drops is 1: Pad wear and 2: Leaking. Might be something worth looking into.

3 Likes

+1
However, I consider that situation to be “something mandatory to look into”.
Brake fluid doesn’t evaporate, so if the pads are showing almost no wear, then there has to be a leak in the brake hydraulic system, and that is… not good.

3 Likes

13 years from the factory… if system was maintained and fluid was regularly flushed (at least 6 times by now), I bet it’s not yet “too old”, but if it has the original fluid… I would not be surprised if rubber seals and hoses decay

I have had the truck for about 2 years now. I made the mistake of misidentifying the stain on the reservoir for the fluid level. I have no idea of the maintenance before me. I saw no signs of a wheel cylinder leaking and see no leaks at the calipers. I know brake fluid doesn’t just disappear, so I will have to keep an eye on it.