POWER TAKE-OFF (PTO)
Peterbilt Motors Company 8-13
PTO mode. This can be done by using the PTO activation switch on the PTO to close a circuit between pin 2 and pin 1
(chassis ground) of the chassis PTO connector. This will also activate the dash icon to notify the operator PTO mode is
engaged. The chassis PTO connector is located inside the rail adjacent to the transmission as shown in Detail “C” of
Figure 8-20.
PTO OPTIONS
Single acting PTOs have a single air control. A single chassis node output controls the air solenoid, and the air pressure
engages the PTO, and the lack of air pressure at the control port disengages the PTO from the driveline.
Double acting PTOs have a dual air control. One air controls the engagement, and one air control controls the
disengagement. This can be achieved one of two ways:
1) A Single Acting PTO is configured. The engage air control port is connected to the chassis node output and a
pilot inversion valve in the chassis air plumbing is connected to the second disengage air control port
2) Two chassis node outputs control the PTO. One chassis node output and solenoid is connected to the engage air
control port of the PTO, and one chassis node output and solenoid is connect to the disengage air control port.
Reversible PTOs have three different operational states:
1) Inactive, not engaged to driveline, no air control ports active
2) Main Direction, engaged to driveline, Main air control port pressurized
3) Opposite Direction, engaged to driveline, Opposite air control port pressurized
The CECU software is written as part of 3-position switch design strategy. This 3 position switch prevents the possibility
that both inputs are active at the same time.
CECU INTERFACE WITH PTO CONTROLS
If the vehicle is specified with a PTO installation from the factory a protected PTO on/off switch will be present in the dash.
If the truck has the option for EOA PTO controls, it will connect to the instrument panel harness with a switch connector
labeled "EOA x" x being a number between 1 and 10. If numbered between 1 and 8, the switch will be connected to the
Cab ECU.
FIGURE 8-21. Chassis Node / EoA Diagram
If numbered 9 or 10 the switch will be wired directly to EOA valve 9 or 10.
