GMC 2010 Sierra - Manual (Page 168)

Active Fuel Management™
Vehicles with V8 engines may have Active Fuel
Management™. This system allows the engine to
operate on either all or half of its cylinders, depending
on the driving conditions.
When less power is required, such as cruising at a
constant vehicle speed, the system will operate in the
half cylinder mode, allowing the vehicle to achieve
better fuel economy. When greater power demands are
required, such as accelerating from a stop, passing,
or merging onto a freeway, the system will maintain
full-cylinder operation.
If the vehicle has an Active Fuel Management™
indicator, see DIC Operation and Displays (With DIC
Buttons) on page 4‑50 or DIC Operation and Displays
(Without DIC Buttons) on page 4‑59 for more
information on using this display.
Automatic Transmission Operation
If the vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Vehicles with an automatic transmission have an
electronic shift position indicator within the instrument
panel cluster. This display comes on when the ignition
key is turned to the ON/RUN position.
There are several different positions for the shift lever.
Hydra-Matic ® 4-Speed
Automatic Transmission
Heavy Duty 6-Speed Automatic Transmission Shown
(Light Duty 6 Speed Similar)
See “Range Selection Mode” later in this section.
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