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ABS light and parking brake light comes on randomly

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by joshuaT, Oct 3, 2012.

  1. joshuaT

    joshuaT Member

    While driving our new z71, we've noticed the abs light and parking brake light will come on while driving then go off randomly. I looked at the brake fluid level and it looks fine but our front brakes squeak. The guy said he did the brakes before we got the truck. What do you think?
     
  2. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts

    It could be a bad front wheel bearing. When a bearing is bad enough, when you hit a bump the abs sensor wheel or gear can rub on the sensor causing a misread and causing the brake light to come on. I suggest jacking up the front end and giving both front wheels a good shake. Back and forth, up and down. If you have a really bad bearing you will know it when you do this. You can also spin the tire when it is up, does it sound crunchy?
     
  3. mfleetwood

    mfleetwood Rockstar 4 Years ROTM Winner 5000 Posts

    If you have changed the settings in your truck's computer to adjust for tire size, that could be what's causing the parking brake and ABS lights to come on, especially at higher speeds. I've tried both Superchips and Predator tuners and both caused the same problem. If you check their websites/forums, you'll find that this is a common problem with later model GMCs/Chevys and cannot be fixed (at least with those two brands). However, I haven't looked into in a while, so there may be an update out there that corrects this issue.

    If you don't have a tune that incorporates a larger tire size, then I'm not sure what the issue could be. What year is your vehicle? And any other vehicle information you could provide will be great, as it will help members here help you.
     
    Last edited: Oct 3, 2012
  4. joshuaT

    joshuaT Member

    2002 Burb z71 with 16 inch wheels with BF Goodrich TA tires LT265/75R16.
     
  5. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    This is slightly off topic but relates to mfleetwood's comment. What he describes happens to DiabloSport tuners, too. The issue isn't with any of the tuners, but rather with the truck's computer being finicky about tire size and only liking certain sizes. Mine did it when I input 34.5" tires ... but did not do it with 34" tires. Thus, the solution is to find (by trial-and error) the closest size that the computer will accept without triggering the idiot lights. There's not really anything that can be done by the tuner manufacturers since the problem is on the vehicle end...
     
  6. joshuaT

    joshuaT Member

    To my knowledge there was nothing done to the computer but how would I check and see if there was something added?
     
  7. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    I don't think it's computer-related. I think OEM tire size was 265/70R16 on 02 burbs. Your profile is 75 ... so they're a tad taller. If your vehicle is like my 04 it won't notice the difference ... and most people wouldn't take a tuner to the truck to program for it. (The tuner would also be VIN locked to the truck, so they'd pull the tune off prior to sale in order to continue to have a working tuner!)

    I think Pikey's on the right track, it sounds mechanically induced or like it could be an electrical connection that's shorting sporadically due to the truck's motion.
     
  8. mfleetwood

    mfleetwood Rockstar 4 Years ROTM Winner 5000 Posts

    Agree, it is something with our vehicles, and yes you can manipulate the tire size to correct so then it comes down to how much you can tolerate your speedometer being inaccurate vs the lights popping on. I had to lower mine an inch and that threw my speedometer too far off for my level of comfort, so I just put up with the lights coming on occasionally. Yes off topic slightly but this info may be of help to others that may catch this thread looking for this type of information based on the thread title.
     
  9. mfleetwood

    mfleetwood Rockstar 4 Years ROTM Winner 5000 Posts

    x2, as far as I know, that's only later model vehicles
     
  10. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Agreed. Strictly NNBS, I think?
     

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