C3991

C3991 Ford engine fault code diagnosis, code meaning,symptoms and how to fix it.

C3991 Diagnosis

The PTO 1 output circuit is commanded OFF, but air pressure is detected at the pressure feedback switch. Troubleshoot for PTO 2 air solenoid fault, and for air pressure switch short circuit fault.The wiper switch is in the OFF position and the BHM park input from the wiper motor is not in park position. Troubleshoot for a wiper motor park switch circuit fault.

When the engine is in idle or in low engine speed and torque condition, the differential pressure over the DPF is expected to be close to zero. If the differential pressure exceeds a threshold then the differential pressure sensor plausibility DTC is set.

Ford C3991 Fault Code Meaning :

Ford C3991 Symptoms :

Ford C3991 Reasons :

How To Fix Ford C3991 Trouble Code ?

Which Ford cars have the code C3991?

  • C3991 Ford Aerostar
  • C3991 Ford Bronco
  • C3991 Ford C-Max
  • C3991 Ford C-Max Energi
  • C3991 Ford C-Max Hybrid
  • C3991 Ford Contour
  • C3991 Ford Crown Victoria
  • C3991 Ford EcoSport
  • C3991 Ford Econoline
  • C3991 Ford Edge
  • C3991 Ford Escape
  • C3991 Ford Escape Hybrid
  • C3991 Ford Escort
  • C3991 Ford Everest
  • C3991 Ford Excursion
  • C3991 Ford Expedition
  • C3991 Ford Explorer
  • C3991 Ford Explorer Sport Trac
  • C3991 Ford F-150
  • C3991 Ford F-250
  • C3991 Ford F-350
  • C3991 Ford Fiesta
  • C3991 Ford Flex
  • C3991 Ford Focus
  • C3991 Ford Focus Electric
  • C3991 Ford Freestar
  • C3991 Ford Freestyle
  • C3991 Ford Fusion
  • C3991 Ford Fusion Energi
  • C3991 Ford Fusion Hybrid
  • C3991 Ford Fusion Plug-In Hybrid
  • C3991 Ford GT
  • C3991 Ford Mustang
  • C3991 Ford Mustang Mach-E
  • C3991 Ford Mystique
  • C3991 Ford Probe
  • C3991 Ford Ranger
  • C3991 Ford Taurus
  • C3991 Ford Taurus X
  • C3991 Ford Tempo
  • C3991 Ford Thunderbird
  • C3991 Ford Transit
  • C3991 Ford Transit Connect
  • C3991 Ford Windstar

A code is a fault code and it indicates that something has gone wrong with your car's engine.

It can be caused by many different problems, including a faulty battery, a bad fuel pump, or even a cracked exhaust manifold.

You will need to diagnose the problem before you can fix it. The best way to do this is with an OBD scanner tool.

A scan tool will tell you what needs fixing and how much it will cost in order to fix that particular issue.