LS2Ttype

iTrader: (9)

Car was already SD dyno tuned, a week later i put on New tires , They are
27" to maybe 27.25" tall , 295/45/17 Micky drag radials. Nice tires and work great!

stock 275/40/17 areabout 26" and the tires i had on befor were BF 315/35/17 they were only about 25.5" tall

after i put on the Mickys , at around 50 MPH high way driving the ABS inop and break light comes on, I heard its for the Vechial speed sensor , it sees front vs rear wheels spinning at different speeds now,

My tuner, and a good one doesnt know how to adjust for this,

What can i do to fix this
PLEASE HELP

badcoup

There's not much you can do about it. The ebcm sees a discrepancy in speeds because of the difference in sizes. The brake sensors are independent of the PCM so a change there won't fix it.

pro94lt

pull the bulb, you'll forget you ever did

TrippyJoey

iTrader: (1)

I believe you could just get a handheld tuner and recalibrate the speedometer to calculate the speed correctly so that the ABS brake sensor won't go off. What's happening is that due to the different tires the sensors on the ABS detect a discrepancy with the speed detected by the VSS on the transmission tailhousing and the speed detected by the ABS making it think that the tire is either slipping or locking up.

LS2Ttype

iTrader: (9)

OK Joey thats sounds right, Now if i get a hand held to correct this , will it affect my custom SD tune, The car makes 740 RWHP, and i dont want to mess with the tune, Carmen mostlikly lock out my ECM but he can unlock it just to correct for the tire size, i know you can correct for tire size and Gearing if you changed to 373 or taller gears

TrippyJoey

iTrader: (1)

I'm not sure it just depends from which brand you buy. You should look up a used handheld on here or on ebay for a good price and once you do check with the company that makes it before buying it and I'm sure they can answer software specific questions like those better than me.

badcoup

the abs sensor is indepedant of the vss a speedo recalibration won't correct the problem

LS2Ttype

iTrader: (9)

OK so now we are saying a hand held wont correct the difference for the taller tires???

I had a Predator hand held a few years ago, and it corrected for tire and gear changes, i am sure this was to prevent the lights on the dash from turning on.

TrippyJoey

iTrader: (1)

I've heard and read, although I don't guarantee it 100% just giving my own 0.02 here, but when you change to a different tire size that is 3+% bigger or smaller it cause problems with the abs sensor causing the light to go off and making the abs temporally inoperational. And an easy way to solve it is to recalibrate the speedometer so that it will pickup the correct speed rating and not make the abs think that the tires are slipping or locking up.

LS2Ttype

iTrader: (9)

Has anyone had a dyno tune then changed to taller tires , have a light come on due to the taller tire, and then use a hand held to corrcet the difference???

if so i will buy a prediator programmer again and have carmen (vette dr) unlock my ecm so i can fix the issue

TrippyJoey

iTrader: (1)

Try asking one of the dyno specialized sponsors.

ahhwataday

iTrader: (7)

I think the tire sizes have to be within 1.5" difference. Ive had no abs for over a year. Sometimes its not a very big deal but when in a tight spot you will wish it was there.

My fronts are 24.03 and rears are 28.45

LS2Ttype

iTrader: (9)

my car is not a daily driver but i like my abs working

dschmittie1

iTrader: (64)

Correcting the Speedo will not fix your ABS issue. The only way you will fix this problem is if you put the same size tire on the front and rear of the vehicle. The ABS modual is turning on the light because it see a difference in speed of the front and rear wheels. There is NO way to tune this out.

RE AND CHERYL

iTrader: (31)

This is 100% correct. Your tire size is outside of the alowable discreptancy for the ABS ECM. Nothing you can do but select tire sizes that are closer in size. I would stay with tires that have a difference of less than 1 inch to be safe. Since you just bought new rear tires, try increasing the height of the front tires.

Re'

tording99Z28

iTrader: (3)

Pull the ABS system out and install a proportioning valve. The car will actually probably stop better and will weigh less.

LS2Ttype

iTrader: (9)

Ill pull the bulb

TunerGuy

pull the fuses or unplug the ABS it will be easier, then pulling the dash to remove the bulb.
F-body's ABS system does not use the high spedd pulde to supply the rear signal for the ABS, like a lot of the other vehicle do. The dealer might be able to program a diffent tire size in the ABS module, but i've never tried to have it done. 5% differance use to be the magic number to trip the light on the older sustems, I'm not sure it still is or not

Detoxx03

iTrader: (14)

My light comes on too when I put the 295/45/17 mickey's on but I think nothing of it

airforcemanss

iTrader: (23)

so...is the only concern the abs light or does something actually happen besides the speedo being off? how much is the speedo off? im in the market for tires and the mt 295/45/17 is what i want.