GMC 2010 T-Series Owner's Manual page 51

The alarm means that your engine will shut down. See
Engine Shutdown Warning Light on page 3 35 for more
information.
Pull off the road and shut off the engine. Do not start it
until the vehicle is repaired. If the engine shuts down
while you are still in traffic, the engine can be restarted
for another 25-30 seconds of operation. In this
condition, the engine speed remains at idle, and will not
increase even if the accelerator pedal is pressed. The
engine will not shut down until the vehicle speed is less
than 5 mph (8 km/h).
Notice: If you try to operate the vehicle after the
engine automatically shuts down, you may damage
the vehicle. Have the vehicle repaired as soon as
possible.
Idle Shutdown
If the vehicle has a diesel engine it could have an
engine idle shutdown feature.
This feature automatically shuts down the engine after it
idles continuously for five minutes and if the following
conditions are met:
The parking brake is set.
The vehicle is at a complete stop.
The automatic transmission is in N (Neutral) or
P (Park).
If the parking brake is not engaged, then the engine
shuts down after 15 minutes of continuous idling
operation.
The driver can reset the engine shutdown timer by
momentarily changing the position of the accelerator,
brake, or clutch pedal or by shifting the transmission out
of P (Park) or N (Neutral). Once reset, the engine idle
shutdown will restart the shutdown sequence described
above, and will continue to do so until the engine shuts
down or the vehicle is driven.
The engine will not go into idle shutdown mode if:
The Power Take-Off (PTO) equipment is operating.
See Power Take-Off (PTO) on page 2 20 for more
information.
The engine coolant temperature is below 60°F. The
engine idle shutdown will be activated once the
vehicle coolant reaches 60°F or above.
The Diesel Particulate Filter (DPF) is in
regeneration mode and the green DPF lamp is
illuminated to notify the driver that DPF is
regenerating. The engine idle shutdown mode will
be overridden for the time necessary to complete
the regeneration process, up to a maximum of
30 minutes.
Service or maintenance is being performed on the
engine. The engine idle shutdown mode may be
deactivated, by using a diagnostic scan tool, for a
period of up to a maximum of 60 minutes.
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