Expedition 4WD V8-5.4L VIN 5 (2006)
Power Take-Off: Description and Operation
POWER TAKE-OFF (PTO) SWITCH AND CIRCUITS
The PTO circuit is used by the PCM to disable some of the on-board diagnostics (OBD) monitors during PTO operation. The PTO switch is normally
open. When the PTO unit is activated, the PTO switch is closed and battery voltage is supplied to the PTO input circuit. This indicates to the PCM that
an additional load is being applied to the engine. The PTO indicator lamp illuminates when the PTO system is functioning correctly and flashes when the
PTO system is damaged.
When the PTO unit is activated, the PCM disables some OBD monitors, which may not function reliably during PTO operation. Without the PTO circuit
information to the PCM, false diagnostic trouble codes (DTCs) may be set during PTO operation. Prior to an Inspection/Maintenance test, the vehicle
will have to be operated with the PTO disengaged long enough to successfully complete the OBD Monitors.
PTO CIRCUITS DESCRIPTION
The 3 PTO input circuits are PTO mode, PTO engage, and PTO RPM.
The PTO engage circuit is used when the operator is requesting the PCM to check the needed inputs required to initiate the PTO engagement.
The PTO RPM circuit is used for the operator to request additional engine RPM for PTO operation.
