First off I have a 2001 Pontiac Sunfire with the 2.2 L and standard transmission. My ABS light has been on for a few months now and I'm now trying to get it fixed with the weather turning bad here in Colorado.

I pulled all the codes. (see list below)

UNK - B0005 - In Park Switch Circuit Malfunction
PCM - U1000 - Class 2 Communication Malfunction
UNK - B2965 - key in ignition fault
PCM - P0420 - Catalyst System Low Efficiency
DIC - U1000 - Class 2 Communication Malfunction

I believe the B0005 is a different issue (had the park brake on for a while when driving).
I believe B2965 is also a different issue, because I can pull the key out of the ignition while its running without turning it and the car will continue to run. This is probably what turned this code on I'm guessing.
P0420 is because I need to replace the catalytic converter.

So this only leaves codes U1000. I find it unusual that there are no ABS related codes. I don't really know where to go from here though. What to check or what might need replaced. Any advice or insight into what I need to do to get the ABS working again would be greatly appriciated. I'm not much enjoying driving in the snow and ice without it...haha