See also:

How the System Works
URPA comes on automatically when the shift lever is moved into R (Reverse). A single tone sounds to indicate the system is working. URPA operates only at speeds less than 8 km/h (5 mph). An obstacle ...

Warning Lights, Gauges, and Indicators
Warning lights and gauges can signal that something is wrong before it becomes serious enough to cause an expensive repair or replacement. Paying attention to the warning lights and gauges could preve ...

Under the Hood
The Yukon Hybrid uses a two-mode hybrid system. The system augments the SUV's V-8 engine with two electric motors, both powered by a 300-volt battery pack. A cylinder-deactivation system cuts powe ...