Chevrolet/GMC 6.6L Duramax Diesel Engine Supplement (GMNA-Localizing-
U.S./Canada-13337828) - 2020 - CRC - 4/17/19
18 Driving and Operating
.
Engine coolant temperature
reaches 65 °C (150 °F).
.
Air intake temperature reaches
0 °C (32 °F).
The high idle speed will be
temporarily interrupted and the
engine speed will return to normal if
any of the following conditions
occur:
.
The brake pedal is applied.
.
The accelerator pedal is
pressed.
.
The transmission is shifted out
of P (Park) or N (Neutral).
.
Vehicle speed is detected.
Once these inputs are removed, the
engine idle speed will slowly ramp
back up to high idle after the normal
delay, if the conditions for engine
coolant temperature and air intake
temperature are still met.
Fast Idle Control
If equipped, this system can be
used to increase the engine idle
speed.
Fast Idle control will be enabled
when the following conditions
are met:
.
The parking brake is set.
.
The transmission is in P (Park)
or N (Neutral).
.
The vehicle speed is about
0 km/h (0 mph).
.
The cruise control Set switch is
pressed and released for Preset
Fast Idle Speed (1200 rpm).
Fast Idle control will be disabled
when one or more of the following
conditions occur:
.
The cruise control Set switch is
pressed and released. See
“Cruise Control” in the owner ’s
manual.
.
The cruise control Cancel switch
is pressed.
.
The brake pedal is pressed.
.
The transmission is shifted out
of P (Park) or N (Neutral).
.
The parking brake is released.
.
The vehicle speed is not
0 km/h (0 mph).
Winter Cover
If equipped, the winter cover can be
used to enhance heater
performance in extremely cold
conditions below −4 °C (25 °F). The
winter cover installs over the grille
and restricts airflow to the engine
compartment.
For vehicles that did not come with
a winter cover, a GM winter cover
can be purchased. See your dealer
for additional information.
When the winter cover is in use, the
heater, ventilation, and air
conditioning AUTO mode may not
function properly. Use the manual
settings for comfort.
Usage Guidelines
The winter cover should only be
used while operating the vehicle in
extremely cold temperatures or in
heavy snow for extended periods. In
these temperatures, the vehicle
does not need a large amount of air