U055B code meaning
Invalid Data Received From Special Purpose Vehicle Control Module B
What U055B means
U055B concerns the second slot reserved for special purpose controllers. A receiving module gets frames from controller B, but a signal lies outside its permitted span, a counter or checksum is wrong, or the frame length does not match. No manufacturer documents U055B publicly. How freely these slots are filled shows in Deutz's engine controller for off-highway machines, which reports a timeout of its tractor-trailer bridge under U0259, the lost-communication code of slot A. On road vehicles slot B mainly matters when a conversion carries more than one add-on controller, for example separate units for warning lights and for body hydraulics. U025A is the lost-communication counterpart. Only the conversion equipment is normally affected.
U055B at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U055B
- One group of conversion functions fails while others still work
- Fault entry in the receiving module, usually without warning lamp
Common causes of U055B
- Most likelySecond add-on controller set up with wrong address or message set
- PossibleSoftware of add-on controller B and vehicle modules not matched
- PossibleUnstable supply or ground at controller B, e.g. on a shared accessory feed
- Less likelyController B internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Special purpose vehicle module b
What each part of U055B means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5B | The exact fault in that area. |
What to do next
- Note U055B 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 U055B
What does U055B mean?
U055B means "Invalid Data Received From Special Purpose Vehicle Control Module B". U055B concerns the second slot reserved for special purpose controllers. It is a generic code, so it means the same on every make.
Is it safe to drive with U055B?
U055B does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U055B fail an emissions test?
U055B 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 U055B to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U055B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.