U0057
Vehicle Communication Bus D (+) Open
Communication network (CAN bus)
Generic OBD-II
Medium
What it means
U0057 means the positive wire of bus D is open — broken or disconnected — so modules on that network can't communicate. Anything assigned to bus D goes offline, which usually shows up as warning lights and dead features rather than a stalled engine. The fix is finding and repairing the break in the wire or connector.
Medium
Can I keep driving? An open bus wire means modules on bus D are offline — often drivable with warning lights, but check that no critical system dropped off.
Common symptoms
What you'll notice
- Warning lights for the systems on bus D
- Modules on that bus completely unreachable when scanned
- Features tied to those modules dead or defaulting
- Companion 'lost communication' U-codes for the affected modules
Common causes
Most likely first
- Broken or disconnected bus D (+) wire (open circuit)Likely
- A backed-out, corroded, or unplugged connector on the busCommon
- Harness damage from a repair, accident, or rodentsCommon
- A blown feed or broken splice supplying the bus branchLess often
- Internal open in a module's bus connectionLess often
How to diagnose & fix
Work through it in order
- Scan all modules and identify everything on bus D that went silent.
- Consult the wiring diagram and trace the bus D (+) line end to end.
- Check continuity of the (+) wire and inspect connectors for open or backed-out pins.
- Re-seat or repair the broken connection or splice.
- Clear the code and confirm all bus D modules communicate again.
FAQ
Quick answers
Is it safe to drive with U0057?+
If only comfort/body modules are on bus D, it's usually drivable, but the affected safety warnings won't work. Have it repaired before relying on those systems.
Can I just clear U0057?+
No — an open circuit sets the code again immediately. The broken wire or connector must be repaired.
Related codes
Often seen with U0057
Read & clear U0057 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX