ABS inop and BRAKE light after C5 wheel swap

[LiquidFire350]

My dad just bought a 98 Z28, and all the tires looked like they could double for a drag radial. Seeing as that he hasn't sold the 94 yet, he took the wheels off of that (which orginally came from a C5 Vette, 245/XX/17, 275/40/18) and put them on the 98.

Now when he punches it, and gets a bit of wheel spin, the ABS Inop and BRAKE lights come on. They go off when he turns the car off, but come back on if he spins the tires. He hasn't yet gotten the speedo re-calibrated, but he never had this problem on the 94 Z28.

Anyone have and suggestions, or is it just as simple as the speedo issue?

[Chris 96 WS6]

Maybe the ABS computer doesn't like the difference in wheel speeds front to rear?

[LiquidFire350]

Maybe the ABS computer doesn't like the difference in wheel speeds front to rear?

Thats what I'm thinking, but then why did he not have this problem with the 94?

[Chris 96 WS6]

No idea other than the ABS system/logic units are different/improved.

[LiquidFire350]

Well I finally took it out for my own "test drive". Pretty much comes down like this, if all lights are off, everything works fine. If I turn the ASR off, does as its supposed to. If I start the car and turn the ASR off as soon as possible there are no problems, but if I start moving and then turn the ASR off and drive over 50-60MPH then the ASR OFF/ABS INOP/BRAKE lights come on and neither of those two systems work. This is after he had the speedo re-cailbrated for tire size.

[03slowZ06]

what all has been done to the car? and what about his low trac warning is it working right?

[LiquidFire350]

what all has been done to the car?
lid, not sure on anything else, just bought it used
and what about his low trac warning is it working right?

low trac only comes on when the ABS actually works

[gettinthere]

Just have it programed for the tire size. Mine does it too when I have my slicks and skinnies on. It's due to the fact that you have a taller tire in back and it throws the computer off.

[LiquidFire350]

^^^^ just had that done and its still popping on

[Chris 96 WS6]

Put the stock wheels back on!

[LiquidFire350]

Put the stock wheels back on!

thats what I told him, but they are now on the 94 which hes trying to sell, and those tires look like a slick with a couple lines near the edges.

[03slowZ06]

i dont know liquid. the only thing that i can think of is the same as everyone else is stuck on. and thats the 2 diferent size of tires. front and back. i dont think that your pcm can adapt to that. with reprograming for size its adjusting for the speedo. so unless the fronts have the larger side wall to match the rim diference its going to confuse the system.

[gettinthere]

It's the sizes that are doing it. If tuning didn't fix it, pull the bulbs. :lol:

[LiquidFire350]

Now are you ready for the twister ( i just remembered this), right after he bought the car he swapped the rear wheels because they were so bald, so he had the stock 16" wheels up front and the C5 18" wheels out back, and drove for 2 days like that before anylight showed up. Once he went 17/18 thats when the lights poped up, this weekend im gonna jack it up and check out sensors, wires, reluctor rings, and see if i can find anything.

[gettinthere]

Let us know if you find anything bro.

[CamTom12]

I think you can fix it with a Tech II

[LiquidFire350]

I think you can fix it with a Tech II

tried that too, on a 97 Z28, a 01 Escalade, and a 99 Tahoe, you can play with wheel sizes, a 98 Z28 - nope