DRPelley

I have the same trouble on my 2021 Acadia as described by Kimber W. I noticed that when this happens the battery voltage reading is at 12.7vdc. When I stop and turn the engine off and the back on the voltage is 13.9+vdc and the error message does not appear. When I resume 70+mph the voltage goes down to 12.7vdc and stays rock solid at that value. About an hour passes and the error message returns. Wondering if the connector or the sensor itself is corroded enough to lower the voltage even more and hose up the sensor. This seems to be the only time I get the error message - well into long trips. Also it seems to affect the right side sensor only as the mirror light on the right does not illuminate while the left side is normal in operation. I know that the charging systems fluctuate normally as demand changes. Maybe 12.7vdc is a cliff for proper operation? More on this later. Will discuss with GMC service folks.