Hello, I had a new posi installed upgraded from stock 323 to 3.42. Now my abs inop light is on. The brakes work fine. Not sure what the issue could be? Any ideas? thanks

 

The lower gears is throwing your speedometer off, and the needle is now registering a faster speed than the car is really going.
The ABS/traction control and the vehicle speed sensor (VSS) in the trans are reading two different speeds, and it's confused.
You need to have your computer re calibrated to correspond with the new gear ratio.

 

you alway you always help. As far as driving it is it safe to drive until I get the computer recalibrated?

 

Yeah, it's not going to hurt anything. Your transmission (if it's an automatic) may or may not shift differently since that's tied to the VSS, but you're not going to damage it.

 

If anything, you won't have antilock brakes until you get it retuned.

If the ABS computer takes a crap, you still have normal brakes.

 

On your Camaro, gear ratio makes no difference as far as the ABS is concerned, as the system compares wheel rotational speed, and all four wheels are normally turning at the same rate, regardless of vehicle speed. However, if your car uses a three channel ABS (no traction control), there is a possibility that when the gears were changed, the reluctor wheel pressed on the differential carrier was damaged or left out, or the sensor looking at the reluctor was damaged or left unplugged. If the car is equipped both with ABS and Traction control, everything should work normally except, as previously mentioned, the speedometer will be off, and shift points may be a little strange.

 

The point I was making is the speed relationship between the wheel sensors and the VSS.
Now that the VSS is reading a different (faster) speed than the wheels are going, is that not going to confuse the ABS and/or traction control.

 

To the best I could find out ABS only look at differences in wheel speed, and does not care about drive shaft speed. Traction control also uses the ABS sensors to monitor wheel speed, but also looks at the VSS to determine how much engine power has to be reduced or how much brake has to be applied to stop the drive wheels from slipping. Surry for the confusion,

 

I probably should have added its a 95 automatic. The reluctor wheel was left off of the recent install. Its still on the stock posi. Thanks for the info guys. A little sweat wiped off the forhead.

 

If you don't replace the reluctor wheel the ABS won't work. lol