GMC Yukon Denalid Owner's Manual page 251

Trip Odometer
Press the trip odometer reset stem until TRIP
displays. This display shows the current distance
traveled in either miles (mi) or kilometers (km)
since the last reset for the trip odometer.
The trip odometer can be reset to zero by pressing
and holding the trip odometer reset stem while
the trip odometer is displayed.
The trip odometer has a feature called the
retro-active reset. This can be used to set the trip
odometer to the number of miles (kilometers)
driven since the ignition was last turned on. This
can be used if the trip odometer is not reset at the
beginning of the trip.
To use the retro-active reset feature, press
and hold the trip odometer reset stem for at least
three seconds. The trip odometer will display the
number of miles (mi) or kilometers (km) driven
since the ignition was last turned on and the vehicle
was moving. Once the vehicle begins moving, the
trip odometer will accumulate mileage. For
example, if the vehicle was driven 5 miles (8 km)
before it is started again, and then the retro-active
reset feature is activated, the display will show
5 miles (8 km). As the vehicle begins moving, the
display will then increase to 5.1 miles (8.2 km),
5.2 miles (8.4 km), etc.
If the retro-active reset feature is activated after
the vehicle is started, but before it begins moving,
the display will show the number of miles (mi)
or kilometers (km) that were driven during the last
ignition cycle.
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