Circuit/System Verification
WARNING: This page is about a different car, the 2010 GMC Sierra and 2010 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Observe the scan tool Rear Wheel Speed parameter. The rear wheel speed reading should be within 2 mph of the front speed sensors when driving in a straight line at a speed greater than 20 km/h (13 mph).