Network, generic

U05BF Invalid Data Received From Trailer Backup Assist Control Module

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Trailer backup assist lets the driver reverse a trailer by turning a knob rather than the wheel; the vehicle measures the hitch angle and steers for the chosen path. Ford's Pro Trailer Backup Assist reads the angle from a target sticker via the rear camera or from a sensor on the trailer, and a Ford patent caps the steering command according to how fast the hitch angle changes, so the rig does not jackknife. Ram calls its version trailer reverse steering. On the 2021 Ram 1500 the lost-communication partner U02BE turned up in the ABS, steering and engine controllers with a throttle control message and the MIL, caused by internal module software; pulling fuse 53 restarted the module (STAR S2108000067). No maker documents U05BF; it means the module talks but sends invalid data, and the assist is then blocked.

Likely causes

Internal software fault in the trailer backup assist module
Implausible hitch angle input from trailer target, camera or trailer sensor
Trailer profile incomplete or measured dimensions wrong
Module supply interrupted or connector loose

Symptoms

  • Trailer backup assist cannot be activated or cancels
  • Rear park assist temporarily unavailable
  • Warning messages in other modules, on some trucks with MIL

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–1,200
Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

trailer backup assist module

Related codes

U02BEU0565

References: static.nhtsa.gov, ford.ca, patents.google.com.