Tow Can Mess Up GPS
This bulletin applies to all 2011-2012 GM passenger cars and light-duty trucks. In the event that an OnStar module had previously acquired a GPS signal with calibrated dead reckoning and is transported or towed at least 59 miles with the ignition off, the module may not re-acquire a current GPS location.
This will result in OnStar being unable to correctly locate the vehicle. Note that this condition may also affect compass operation on global A vehicles (Buick LaCrosse, Regal, Verano, Cadillac SRX and XTS, Chevy Camaro, Cruze, Equinox, VOLT and GMC Terrain).
Do not replace any parts for this concern. The technician must remove power from the OnStar module for at least 5 minutes to re-set it. With power re-connected, the vehicle will then need to be driven 5-10 miles and perform two left and two right 90-degree turns to allow the vehicle to re-acquire GPS and self-calibrate the dead reckoning feature.
After re-setting the module and driving 5-10 miles, it may be necessary to turn off the ignition, cancel RAP and turn the ignition back on in order for the compass to display the correct heading on global A vehicles.