Volvo VNL 780 Operator's Manual page 120

110 INSTRUMENTS AND CONTROLS
To increase/decrease engine speed:
1 Volvo engines: Press and release the SET+ or SET- toggle switch to increase/decrease
speed in increments (increment size depends on programmed value).
2 Cummins engines: Press and hold the SET+ or SET- toggle switch to increase/decrease
speed. When the switch is released, the engine speed sets at current speed.
To deactivate PTO speed function:
1. Set the PTO/CC switch to the OFF position.
or
2. Depress the service brake pedal.
or
3. Depress the clutch pedal (Programmable).
or
4. Increase vehicle speed above PTO working range (typically 8 km/h [5 mph]).
Engine Brake
DANGER
When operating your tractor bobtail
(without a trailer) or on slippery roads,
the engine brake switch must be in the
OFF position. Failure to follow these
instructions can result in loss of vehicle
control, serious personal injury or death.
DANGER
A vehicle speed retarding device is not
intended to replace the service brake
system on your vehicle nor intended to
bring your vehicle to a stop. A vehicle
speed retarding device is only intended
to retard the speed of your vehicle under
certain conditions.
Using the retarding device as a brake
could result in loss of vehicle control and
personal injury or death.