Chevrolet Silverado 4500HD 2022 Manual page 258

The PTO load relay engages immediately
when the PTO operation is initiated by
the switch input. The transmission torque
converter is unlocked. The torque
converter will lock upon reaching stable
PTO Standby Speed (default = 900 rpm)
so maximum power is available.
The first elevated engine speed, PTO
Standby Speed, is not intended as a
working speed but as a verification that
the system is active and ready to go to a
working speed.
The relay connections are made at the
PTO Upfitter Connector located on the
chassis frame behind the cab.
The engine speeds can be adjusted
between the low of PTO Standby Speed
and the high of PTO Max Engine speed
limits. Both values can be modified from
the factory default settings with the GM
Service Tool. Based on the value chosen
for PTO Max Engine Speed, the PTO menu
in the center stack may show speeds that
are not available.
Factory setting for the tap step is 100
rpm and the setting for ramp rate is 150
rpm/sec. The default value for tap step
can be modified via the Radio
Customization menu. The default values
for both tap step and ramp rate can be
changed with the GM Service Tool.
The PTO load relay is enabled as the
factory default programmed setting.
Refer to the service manual or go to the
GM Upfitter Integration website
www.gmupfitter.com for details.
Mobile PTO
Mobile Enable Conditions In-Cab
Operation Only
This requires programming with the GM
Service Tool.
1. The engine must be running.
2. The parking brake must be released.
3. Confirm that cruise control is off.
4. Engine rpm must be less than 1500 rpm.
5. Shift the transmission to M1, M2, or M3.
6. Tap the brake pedal and then do not
press the brake pedal.
7. Keep the driver door closed. The driver
door can be kept open if reconfigured
using the GM Service Tool. See
www.gmupfitter.com.
Driving and Operating
8. Press and release the PTO in-cab switch
below the climate controls in the center
stack. Then within 10 seconds press and
release +RES on the cruise control. The
PTO indicator light will blink slowly
between presses. The PTO indicator light
will then blink rapidly until the PTO load
becomes engaged, and then come on
steady. The engine speed will remain at
the current throttle setting or advance to
PTO Standby Speed, whichever value is
greater. If the engine rpm is above 1500
rpm, the PTO relay will not engage until
the engine rpm drops below 1500 rpm.
9. Once engaged, if additional engine speed
is desired, use either the cruise control
or the accelerator pedal to temporarily
adjust the engine speed.
+RES on the cruise control can be used
to tap up, or if continuously held to
ramp up, to the desired operating
speed. SET on the cruise control can
be used to tap down or coast down if
continuously held to the desired
engine speed. Top limit is PTO Max
Engine Speed, default 2100 rpm and
programmable to 2900 rpm. Lower
limit is PTO Standby Speed, default
900 rpm with program range from
base idle to 900 rpm.
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