B3978

B3978 Ford engine fault code diagnosis, code meaning,symptoms and how to fix it.

B3978 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.Determine if the extra switch is not required for the vehicle or if the switch has been installed but the necessary reference parameter has not been programmed into the BHM.

This circuit connects to the CHM as an input at connector J3,P. The CHM passes the signal through to power the tail lamps and marker lamps from connector C2 pin G and also from connector C1 pins D, E, and F.

Ford B3978 Fault Code Meaning :

Ford B3978 Symptoms :

Ford B3978 Reasons :

How To Fix Ford B3978 Trouble Code ?

Which Ford cars have the code B3978?

  • B3978 Ford Aerostar
  • B3978 Ford Bronco
  • B3978 Ford C-Max
  • B3978 Ford C-Max Energi
  • B3978 Ford C-Max Hybrid
  • B3978 Ford Contour
  • B3978 Ford Crown Victoria
  • B3978 Ford EcoSport
  • B3978 Ford Econoline
  • B3978 Ford Edge
  • B3978 Ford Escape
  • B3978 Ford Escape Hybrid
  • B3978 Ford Escort
  • B3978 Ford Everest
  • B3978 Ford Excursion
  • B3978 Ford Expedition
  • B3978 Ford Explorer
  • B3978 Ford Explorer Sport Trac
  • B3978 Ford F-150
  • B3978 Ford F-250
  • B3978 Ford F-350
  • B3978 Ford Fiesta
  • B3978 Ford Flex
  • B3978 Ford Focus
  • B3978 Ford Focus Electric
  • B3978 Ford Freestar
  • B3978 Ford Freestyle
  • B3978 Ford Fusion
  • B3978 Ford Fusion Energi
  • B3978 Ford Fusion Hybrid
  • B3978 Ford Fusion Plug-In Hybrid
  • B3978 Ford GT
  • B3978 Ford Mustang
  • B3978 Ford Mustang Mach-E
  • B3978 Ford Mystique
  • B3978 Ford Probe
  • B3978 Ford Ranger
  • B3978 Ford Taurus
  • B3978 Ford Taurus X
  • B3978 Ford Tempo
  • B3978 Ford Thunderbird
  • B3978 Ford Transit
  • B3978 Ford Transit Connect
  • B3978 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.