U3991

U3991 Ford engine fault code diagnosis, code meaning,symptoms and how to fix it.

U3991 Diagnosis

The fuse in the main PDM powering this circuit may be open. The root cause could be excessive loads on an output, or a short to ground in the VBAT2 supply to the CHM.The BHM supplies battery power on this circuit when the key is in the RUN or CRANK positions. Troubleshoot for a wiring fault shorting this circuit to ground or for too many optional circuits spliced into it that is causing the BHM to turn it off.

When the engine is in higher engine speed and torque condition, the differential pressure over the DPF is expected to rise according to engine speed and torque. If the differential pressure exceeds a threshold then the differential pressure sensor plausibility DTC is set.

Ford U3991 Fault Code Meaning :

Ford U3991 Symptoms :

Ford U3991 Reasons :

How To Fix Ford U3991 Trouble Code ?

Which Ford cars have the code U3991?

  • U3991 Ford Aerostar
  • U3991 Ford Bronco
  • U3991 Ford C-Max
  • U3991 Ford C-Max Energi
  • U3991 Ford C-Max Hybrid
  • U3991 Ford Contour
  • U3991 Ford Crown Victoria
  • U3991 Ford EcoSport
  • U3991 Ford Econoline
  • U3991 Ford Edge
  • U3991 Ford Escape
  • U3991 Ford Escape Hybrid
  • U3991 Ford Escort
  • U3991 Ford Everest
  • U3991 Ford Excursion
  • U3991 Ford Expedition
  • U3991 Ford Explorer
  • U3991 Ford Explorer Sport Trac
  • U3991 Ford F-150
  • U3991 Ford F-250
  • U3991 Ford F-350
  • U3991 Ford Fiesta
  • U3991 Ford Flex
  • U3991 Ford Focus
  • U3991 Ford Focus Electric
  • U3991 Ford Freestar
  • U3991 Ford Freestyle
  • U3991 Ford Fusion
  • U3991 Ford Fusion Energi
  • U3991 Ford Fusion Hybrid
  • U3991 Ford Fusion Plug-In Hybrid
  • U3991 Ford GT
  • U3991 Ford Mustang
  • U3991 Ford Mustang Mach-E
  • U3991 Ford Mystique
  • U3991 Ford Probe
  • U3991 Ford Ranger
  • U3991 Ford Taurus
  • U3991 Ford Taurus X
  • U3991 Ford Tempo
  • U3991 Ford Thunderbird
  • U3991 Ford Transit
  • U3991 Ford Transit Connect
  • U3991 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.