"Service Power Steering" on DIC. Battery dies every 24 hours if car is not driven around to charge it. Third new good tested battery. Alternator tests good. Happens with all the batteries. All problems started within a week of each other.

Car is in new condition only 15k miles on it but out of warranty. All connections clean and tight.

Have seen many things online about similar problems on Equinox and Terrain. But no solutions.

 

I paid $200 at the GMC dealer who told me they wanted $2000 to replace the ABS module and associated valves. Showing DTC U0121.

My question is: Is there any other (less expensive) alternative cause for these symptoms and this error code. "4 modules not communicating to Electronic Brake Control Module" seems to imply it could be any number of things on the CAN bus as simple as a corroded connector or broken wire somewhere. But the dealer seemed to jump all the way to the most expensive possible option. Am I wrong?

Does anyone have any experience with the issues I've described and/or the DTC being thrown from something else besides the module or is that the only possible explanation/fix?

Again this is for a 2013 GMC Terrain 2.4 with only 16k miles on it. It is in brand-new condition hardly ever driven and kept inside a garage 99.9% of the time.