I have spent hours, days, weeks searching for the answer to this and for some reason it seems to be the best kept secret ever. I don't understand.

I am trying to find out if there is a free or cheap Android or Windows PC app that will work for diagnosing all or most codes (not just the P / CEL codes) like B, C and U for GM.GMC vehicles. I have an assortment of ABS and Brake related lights on and cannot believe it is this hard to figure out what the story is. Surely you guys know where to point me that isn't a scan tool so expensive that is about the same as a shop would charge.

Thanks.

 

Might be you could have an auto parts store run a more expensive OBD II scan-tool on your vehicle, rather then buying one of the more expensive ones, not the $35 dollar ones that wont run the other OBD II codes you mentioned.