Engine Fan - Chevrolet GMC Duramax 2023 Manual

If the Action Required - Idle Vehicle To Cool
Engine DIC message displays, do not turn
the engine off. Keep the engine running
until the message goes away.
Intended Vehicle Use: After a Heavy
Towing Event
If equipped, when the vehicle is turned off
after towing heavy loads, the system may
automatically restart the engine. A chime
will sound and DIC messages will display.
The engine will automatically turn off after
10 15 minutes of run time or if enough
cooling has occurred.
If the DIC messages display after the vehicle
has been stopped and placed in P (Park)
with the engine still running, remain in the
vehicle with the engine running until these
messages no longer display. It may take up
to 15 minutes of idling. Do not park the
vehicle in an enclosed area if the messages
display.
If the system determines that the engine
should be restarted and the ignition is
turned off, the engine will turn off and then
automatically restart. If the engine is
restarted, DIC messages display and chimes
will sound. The vehicle cannot be shifted out
of P (Park) unless the feature is overridden.
Never leave occupants in the vehicle, and
always take the keys and lock the doors if
you must leave the vehicle idling. Some
local laws prohibit a vehicle from idling
unattended. Always remain with the vehicle
until it automatically turns off. This could
take up to 15 minutes.
If the system determines that the vehicle
was not allowed to restart, or if a condition
such as an open hood has been detected,
then DIC messages display and a chime will
sound. To help with system performance,
either restart the engine, or if the engine is
not running and the hood can be safely
opened after one minute, open the hood to
allow cooling.
If the system has automatically restarted
the engine, the vehicle cannot move until
cooling has completed and the engine
automatically turns off. Overriding this
feature will allow normal vehicle operation.
To override, start the vehicle as you would
normally. Then either drive the vehicle as
normal or turn off the ignition if you must
exit the vehicle. Opening the hood will
prevent the restart or will turn the engine
off when this feature is active.
Vehicle Care
Interactions with Manual Regen
If the system has determined that the
engine should be restarted, then the manual
regen feature will not be allowed.
If manual regen has been enabled, and the
system has determined that the engine
should be restarted, there will be no chime
or DIC messages related to the Diesel Engine
After Run Feature until the manual regen
completes. If the engine is turned off during
the manual regen, a restart may occur
without any alerts.

Engine Fan

The vehicle has a clutched engine cooling
fan. When the clutch is engaged, the fan
spins faster to provide more air to cool the
engine. In most everyday driving conditions,
the fan is spinning slower and the clutch is
not fully engaged. This improves fuel
economy and reduces fan noise. Under
heavy vehicle loading, trailer towing, and/or
high outside temperatures, the fan speed
increases as the clutch more fully engages,
so an increase in fan noise may be heard.
This is normal and should not be mistaken
as the transmission slipping or making extra
shifts. It is merely the cooling system
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