GMC 2.8L Duramax Diesel 2020 Manual page 57

56 Driving and Operating
PTO indicator light will turn off,
indicating the PTO load relay is
disengaged and the stored set
speed has been cleared from
memory.
Mobile Mode will also disengage if:
PTO feedback input is lost. The
engine speed is returned to the
PTO Standby speed setting and
the load is still engaged. This is
configurable with the GM
Service Tool.
Vehicle Speed exceeds Max
Vehicle Speed. Factory default
setting = 94 km/h (58 mph). PTO
relay will re-engage and
advance to the last engine
speed stored in memory when
both the Vehicle Speed is
reduced below 94 km/h (58 mph)
and the engine speed ramps
down below the maximum PTO
engagement speed (1500 rpm
factory default setting).
Engine Speed exceeds Max
Engine Speed for more than
15 seconds. Factory default
setting = 2100 rpm.
on the cruise control is
pressed.
The parking brake is applied.
The shift lever is moved out of
manual shift selection, M1,
M2, or M3.
Resume memory speed is cleared
for the above actions.
Although the PTO system attempts
to limit accelerator and PTO switch
inputs to comply with maximum
speed and/or rpm parameters, some
vehicle operating conditions such as
downhill acceleration can cause the
vehicle speed or engine rpm to
exceed these limits. In those cases,
the PTO system may disengage.
Operator Selectable In-Cab
Mode (OSIM)
To disable OSIM Stationary PTO:
Press and release the PTO
in-cab switch.
To disable OSIM Mobile PTO:
Press and release the PTO
in-cab switch.
Prolonged or Extended PTO
Operation
When operating the vehicle in
stationary PTO mode, the Diesel
Particulate Filter (DPF) will continue
to filter the exhaust and accumulate
soot. The engine control system,
depending on the speed and load
being applied by the PTO, may not
be able to generate enough energy
or adequate heat needed to
automatically clean or regenerate
the DPF. If manual regeneration is
not initiated, continued operation
under conditions that do not allow
effective regeneration or cleaning
will eventually plug the DPF and
result in reduced power. The
ENGINE POWER IS REDUCED
Driver Information Center (DIC)
message and malfunction indicator
lamp will be displayed, and dealer
service will be required to return the
vehicle to normal, full power
operation. To prevent this from
occurring, frequently monitor the
vehicle during stationary PTO
operation, paying particular attention
to any horn chirps and/or the