Grand Marquis V8-4.6L Flex Fuel (2010)
Power Take-Off: Description and Operation
ENGINE CONTROL COMPONENTS
Power Take-Off (PTO) Switch and Circuits
The PTO circuit is used by the PCM to disable some of the 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 DTCs may be set during PTO operation. Prior to an inspection/maintenance (I/M) test, operate the vehicle 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 when the operator is requesting additional engine RPM for PTO operation.