U05BF code meaning
Invalid Data Received From Trailer Backup Assist Control Module
What U05BF means
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.
U05BF at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U05BF
- Trailer backup assist cannot be activated or cancels
- Rear park assist temporarily unavailable
- Warning messages in other modules, on some trucks with MIL
Common causes of U05BF
- Most likelyInternal software fault in the trailer backup assist module
- PossibleImplausible hitch angle input from trailer target, camera or trailer sensor
- PossibleTrailer profile incomplete or measured dimensions wrong
- Less likelyModule supply interrupted or connector loose
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Trailer backup assist module
What each part of U05BF means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| BF | The exact fault in that area. |
What to do next
- Note U05BF and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U05BF
What does U05BF mean?
U05BF means "Invalid Data Received From Trailer Backup Assist Control Module". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with U05BF?
U05BF does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U05BF fail an emissions test?
U05BF is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U05BF to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will U05BF clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.