Power Take Off
WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The PTO system provides an input signal to the PCM indicating there is an additional load being applied to the engine. The PCM disables the on-board diagnostic (OBD) monitors and increases the engine RPM based on the PTO system or auxiliary idle control input.