bartlettj wrote:
The basic OBD code readers can only get to the ECU. The other modules like ABS and Body Control require manufacturer specific protocols that your typical AutoZone reader can't get to. If you don't want to go to the dealership I would go to a diesel shop at least.
Maybe first check the rear wheel sensors, I hear that wheel bearing and brake rotor wear will affect them.
You can buy ones that ABS/ECM/BCM. I have one in my garage. Reads transmission, wheel sensor, stabilitrak and real time data. It was 180 dollars. There are tons out there that do that.
Some VW required the use of VAG Com, but these have those scanners too.
You do not need manufacture specific to read codes. If you wish to program a sensor (CPS, steering position sensor etc) in a GM you need GM Tech2 or something like HP tuners which I have for the WS6.