Hello, it seems that I'm having a bit of trouble with my wheel speed sensor. I recently replaced just my back tires with 225/65 as opposed to the stock 225/55 well now after driving for about 10 minutes (depending on how fast I drive) my brake light and my ABS INOP light will come on and my ABS will stop working (before the light comes on my ABS will work fine). I posted this over in the section for my car and they said that it might have something to do with the different sized wheels rotating at different speeds and that I would have to get my ABS re-tuned. My question is, how is this done? If the ABS is tied to the PCM then can I get the ABS re-tuned when I get my PCM re-programmed?

Oh, I forgot to mention. I have a '98 V6, if that changes anything.

 

Your problem isn't with the ABS, it's with the tires.
The ABS system has speed sensors on all four wheels. Under normal circumstances, if one of the wheels is registering a different speed from the rest, the computer will read it as tire slip and will adjust traction control accordingly.
For comparison, I looked up a set of General tires in both your sizes.
The 225/65 is 27.5" in diameter and turns 756 revolutions/mile.
The 225/55 is 25.7" in diameter and turns 811 revolutions/mile.
That's a whopping difference for you to be running both those sizes, and it's enough to confuse your computer's ABS system.
If you have mixed brands of tires from front to back, the differences between them could be greater, or it could be less since tire diameters aren't all the same between brands, even though they are the same aspect ratio.
I think it would be a lot easier, cheaper, and less farting around to just get another pair of tires to match the new ones. In the meantime, you can run what you have, but your ABS will just be inop.

 

Thanks for the advice, unfortunately, tires aren't cheapand I'm pretty strapped for cash ATM. Is there any chance that it will hurt my car running the way it is?