ABS Light on start up

[S76GUY]

99 NBS Silverado. I am getting the ABS and Brake light on start up.

When I first installed the tune this would happen only after a few miles of driving. I corrected it by changing tire size and it hasn't been a problem.

But this is something new. Please help.

[sseeya2001]

Welcome to the club, a few of us on here been trying to get answers for this for quite some time now...

[moose4797]

yup

[mikel]

99 NBS Silverado. I am getting the ABS and Brake light on start up.

When I first installed the tune this would happen only after a few miles of driving. I corrected it by changing tire size and it hasn't been a problem.

But this is something new. Please help.

so, ahs anything chnaged since you were not getting hte light?

[sseeya2001]

For me, I inputed the tire size and it would take a few minutes longer to come on. My daily commute is less than 5 minutes, so I didnt notice the lite coming on until, I went on a longer drive, now it comes on when i have been driving around ten minutes or so. Havent adjusted anything else on the truck or had anything done.

[Dschev1]

Gm issued a recall recently about the area under the driver seat getting damp and retaining moisture.
My letter stated that the seat belt lock would/ could lock up and not release properly, or stick , and the ABS and or Brake light could illuminate and in extreme cases the bag could deploy.

As far as the wheel size settings go, if your down to where it takes 10 minutes to kick the lights, you are close. try a couple weird sizes, example my factory wheels were 245/70/17, I installed 265/70/17 but had to program my wheel size to 245/66/17 to get my lights to stay off with the 93 oct. then 245/68/17 with the 87 oct tunes. Just a thought, I know I was frustrated and spent months working on my lights..

[mypostoffice]

Check your glove box door, inside, for one of the following codes: "JF3" or "JF7"; if your see either of these codes, you've purchased one of Chevy's rare phenomenons. Concisely, the codes above represent two ABS module manufactures; said modules cannot be re-programmed, period! The modules remain related to an ABS towing option, normally on work trucks. Regardless, if you see JF3 or JF7, you can't resolve the issue with any combination of programmers and or odometer add-ins; trust me, I've tried.

If you want the brake or ABS light out, simply lie to the tuner concerning tire size. I'd recommend rolling out your true tire diameter, with chalk, on pavement; and step your tire sizes down until the light extinguishes, likely near the tire diameter on the driver's door tire label (hint, hint). Finally, JF3 or JF7 are l@@king for near OEM parameters; and anything outside those parameters, you get a wondrously illuminated ABS/Brake light indication! Henceforth referred to as the "ABS Annoyance Light."

Note: this remain especially true concerning gear changes! ouch!

[concoursd]

wow, finally a rational answer to all of the finger pointing by ABS light customers on this forum.