donbrew. Mine is a 2010 and I don't get an error code. Special tool? The one time I did reset it, I used the horn "beep" method.

I think you're incorrect, or, I'm reading your post wrong.

 

"In 2010" does not imply all of 2010. Sometime in 2010 GM changed the programming mostly for the 2011 models, SOME 2011s use the old reset MOST use the new "need the tool" procedure. Now all GM cars use the new system.

GM says they changed because their techs could not reliably reset positions in the shop bay because of all the other cars. So they wanted the consumer to shell out $80 for a Kent Moore EL-50448 tool instead of making the techs drive out to the parking lot.