Rather annoying subject with error codes and abs
 

So here's the thing. I have a 2001 Audi TT roadster that I aquired, but am having issues troubleshooting the Abs and Esp light from going off. The error codes are
Error code 00668----Battery Power Voltage Supply (Terminal 30)

Error code 01278----Electronic Differential Lock Cut-off Relay -J263

if anyone could help me out in solving these problems, it would be greatly appreciated. I have never encountered a problem like this on either of my tt's and I need this to pass a brake and light inspection to get this legal on the road.