GMC 2010 T-Series Owner's Manual page 70

Manual Cleaning Procedure
WARNING:
During DPF self cleaning, the exhaust system and
exhaust gases are very hot. Stay clear of the
tailpipe area and do not park over things that
burn. You or others could be burned or the vehicle
could catch fire. See Parking Over Things That
Burn on page 2 27.
If the yellow or red DPF indicator is on, you can clean
the DPF by performing a manual cleaning.
2-30
When it is safe to do so, stop the vehicle. Perform DPF
manual cleaning in a well ventilated area. DPF Manual
cleaning must be performed outdoors, as follows. Once
manual cleaning is started, complete the cleaning in a
single operation if possible. If manual cleaning is not
completed, as indicated by the green DPF indicator
going off, and the yellow or red indicator light remains
on, self cleaning might not be allowed until the vehicle
is stopped and manual cleaning is performed until
completed.
1. Check engine oil and engine coolant levels to be
sure they are at proper operating levels.
2. To prevent running out of fuel during manual
cleaning, make sure there is at least a quarter of a
tank of fuel.
3. Check to make sure the area near the exhaust
tailpipe and under the exhaust system is clear of
any materials that could catch fire. Keep people
away from the area of the exhaust system and
exhaust gases.