All engines have electronic engine speed limiting. The engine limited speeds range between 2,900 and 4,400 rpm depending on engine option content.

This system controls maximum vehicle speed automatically and reduces engine power until vehicle speed gets down to maximum governed speed.

The default setting for C4500 and C5500 models up to 19,500 lbs GVWR is 80 to 85 mph (128 to 136 km/h). Most other models have a default setting of 75 mph (120 km/h), although some tire sizes and tread patterns may limit maximum speed to 55 to 65 mph (86 to 105 km/h). You may have a label on the headliner of your vehicle with more information on your engine road speed governor. See your GM dealer for assistance with programming your engine limited speed.