To bring this back from the dead, if I get a used ABS Module will it still work if I do not have it re programmed, it will just have a dash light on?

There's no need to have a used module programmed
 

You don't need to have a used module programmed. But you do have to make sure that it comes from a car with like options. I can't remember specifically what the options that matter are, but I think it might just be whether it has dynamic stability control and whether or not it's an auto/manual. I did this several months ago with a used module and I did get an ABS light at first, but it self-corrected after a bit of driving.

Cool, thank you G2.

It’s DSC (traction control) vs non-DSC

Thank you TeamRX8.

Be advised that there are a few RX8 ABS modules w/DSC listed as w/o DSC on eBay etc. I recommend that you understand the physical differences and determine for yourself based on the pictures being provided. Regardless of whether they’re not informed enough to know better or are using pictures not from the actual module, you likely are better off avoiding that seller.

Wanted to share my experience -

Working on a friend's 2004 RX-8 Grand Touring 6-speed. Has DSC of course.

Car would start fine in the morning and you could drive it literally HOURS just fine. When you stopped and shut the car off then started back up you'd get the 3 lights - Brake, ABS, and the skidding traction control car. Using Bluedriver the car would show a code C1096 and C2778.

This also seemed to happen only when the outside temperature was relatively warm - probably over 60 deg F or so. On a 40 degree day, for example, the lights would never end up coming on.

Even if the lights were on, after a full cooldown overnight and cold start the lights would be gone.

So with this thread and others I determined it was most likely the ABS control module. Got one from a friend's parts car - the car was also the exact same spec, 2004 Grand Touring with 6-speed and DSC.

Unplugged and unbolted the old module, bolted on the one from the parts car, and that was it. No programming was needed.

To remove/reinstall the module you will need a Torx T-20 socket. I recommend a 1/4" drive one with a few short extensions and a universal joint. The 3 on the left side of the module are easy, the top right one is easy, the middle right one is tricky and the bottom right one is quite tricky. They can all be removed with the right combo of extensions. If you are really struggling, remove the airbox and unbolt the fuse box and move it out of the way.

So far so good, I've done multiple trips in 70 degree weather with no lights coming on.

Also from Googling around you can use the Forscan software to program an ABS module yourself if it doesn't agree with your car. I imagine this would have to be done with some sort of mismatch like one from an automatic car going in a manual trans car. The process looks quite simple; document old hex code from old module and program that into a new one.

Hope this helps someone going forward!

Dale