U0251Lost Communication With Running Board Control Module B
- Generic OBD-II code · Network
- How the car detects it
- Letter B denotes a second running board controller, which only exists where each side has its own unit. Ford's documented power running boards rely on a single running board control module (RBM): its 2015–2022 bulletins describe one RBM that logs U3003:16 and turns the feature from Auto to Off after a low or flat battery (SSM 50154) and one whose software flips the setting on F-Super Duty (SSM 52411). No manufacturer publishes a vehicle that uses U0251. Under the J2012 scheme, a body controller or gateway would set it once frames from unit B stop. Because such units live under the body near the board motors, water, road salt and stone damage at plugs and wiring are the main suspects. The driver finds the board on one side stuck in or out. Unit A is U0244; invalid data from B are U0552.
- What you may notice
- Running board on one side does not deploy or retract
- Running board fault message in the cluster
- Likely causes
- LikelyWater or salt corrosion at underbody connectors and wiring
- PossibleLow or flat battery that left the module offline
- PossibleModule without power or ground (fuse)
- RareModule internally faulty
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.