U0055 code meaning
Vehicle Communication Bus D
What U0055 means
U0055 covers Vehicle Communication Bus D as a whole, the fourth network slot a manufacturer can assign freely. Volvo documents it for the 2016-17 XC90 T8 plug-in hybrid: the engine control module stores U005500 with fault type intermittent, the driver information display shows the turtle symbol and the car lacks power. Volvo classifies it as a software fault, tells technicians not to replace parts, and announced new software for week 16 of 2017, until then the code was simply cleared. Bentley assigns Bus D to a private chassis CAN and documents its performance code U0056. Without such a bulletin, look first for lost-communication codes that show which module on Bus D is missing, then check its supply, ground and connectors.
U0055 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0055
- Turtle symbol and reduced engine power (Volvo XC90 T8)
- Functions of modules on Bus D unavailable
- Lost-communication codes stored alongside
Common causes of U0055
- Most likelyControl module software misjudging Bus D (Volvo XC90 T8: ECM update)
- PossibleSupply or ground fault at a module on Bus D
- PossibleDamaged wiring or loose connector on Bus D
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bus d wiringBus d nodes
What each part of U0055 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 55 | The exact fault in that area. |
What to do next
- Note U0055 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 U0055
What does U0055 mean?
U0055 means "Vehicle Communication Bus D". U0055 covers Vehicle Communication Bus D as a whole, the fourth network slot a manufacturer can assign freely. It is a generic code, so it means the same on every make.
Is it safe to drive with U0055?
Drive gently and only to a workshop. With U0055 the car can go into limp mode (reduced power) to protect itself.
Will U0055 fail an emissions test?
U0055 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 U0055 to fix?
Difficulty: hard. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will U0055 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.