Abs/brake light

[Snowking]

I have a 2000 gmc with the 5.3. It has 390000 on it. The abs and brake light came on while driving to work this morning. I still have a firm petal the fluid level is good and I put it on the lift and couldn't find a bad line. I pulled over and it went off. Could this be a master cylinder going bad? Any help would be appreciated. Thanks chad

[Macgyver55]

Could be a wheel speed sensor, the ECBM or any number of things. You'll need to get a code to track it down.

If the pedal is firm its unlikely your master cylinder is bad. If it were, the pedal would go to the floor or creep down slowly when depressed. Even if it were bad your ABS light shouldnt come on because of it.

[acroman]

I have had this same problem with my 2003 yukon XL it was a wheel speed sensor. Like Macgyver55 stated you will need to get the coded checked to confirm.

[Snowking]

Do they have wheel speed sensors in the rear? I replaced the both front hubs this past summer. Does the auto parts store have a code checker for the brake system?

[Macgyver55]

Not individual ones like the front. The rear uses a sensor in the transmission that senses output speed of the drive shaft. But again, you would really need to get a code before proceeding since there are several different things it could be.

[Dozer]

Did you put quality hub assemblys in or just cheapos? I put cheap ones in the front of my silverado the first time and had to replace both of them within 2 years because they went bad again.

[Jeremy airjer W]

Did you put quality hub assemblys in or just cheapos? I put cheap ones in the front of my silverado the first time and had to replace both of them within 2 years because they went bad again.

I would have to agree!

Just to clarify... Any time the abs light is on the brake light will also come on. The abs requires the brake system to function BUT the brake system does NOT require the ABS system to function. Anytime the ABS light is on the brakes will continue to function normally with the only difference being that the ABS system will be disabled as long as the ABS light is on.

As mentioned above, scanning for codes is the best place to start.

[Fishinguy40]

Can you get these codes using the code reader from an auto parts store or is it a different scanner?

I have the same issue starting this morning. MY ABS and brake light started flashing and the bell dinging. Stopped after a minute and the lights are now on solid. I have a 2006 Chevy Silverado 1500. I replaced both front hubs in December and I'm wondering if one of the ABS sensors went bad. I checked the connections when I got to work and they are plugged in solid.

[Scott K]

Most parts stores only have a pcm code reader, but I have heard some do have ones for ABS as well. I would check for loose whell bearings.

[Fishinguy40]

I answered my own question regarding the code reader. Went to the Irish parts store, O'Reilly, where I bought the hubs. The code reader did have options to connect/read the ABS computer. I had to search the menu but found it.

I bought another more expensive hub this time. Yes I have to replace the entire hub because of a flaky wheel sensor. They will refund me the cost of the other hub (under warranty) when I bring it back in. Kinda bummed I gotta pull/replace the entire hub instead of just a wheel sensor.

[Jeremy airjer W]

If it is the sensor than the sensor is serviceable without having to replace the entire hub.

If the hub is loose than you would have to replace the entire assembly.