U0056Vehicle Communication Bus D Performance
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U0056 says Vehicle Communication Bus D works, but its traffic is disturbed. Bentley documents it for the Continental GT (2018-20), GTC (2019-20) and Flying Spur (2020): U005600 with symptom numbers 12689537, 12689541 or 12689542 lands in the chassis control unit (address 0074) or in roll control systems 1 and 2 (00D4, 00D5). Bus D is a private CAN there, and its errors pull in a series of suspension codes; the driver sees a red or yellow suspension lamp and a dynamic ride fault message. Bentley has technicians check the connectors and harness of the three units, then update the chassis control software, or replace the unit if it is on another software level. A production change came with a software update. Elsewhere, loose contacts or a resetting node are the usual causes.
- What you may notice
- Red or yellow suspension warning lamp (Bentley)
- Dynamic ride fault message, several suspension codes stored
- Functions drop out briefly and return
- Likely causes
- LikelyChassis control software level prone to Bus D errors (Bentley)
- PossibleLoose or dirty connector at a module on Bus D
- PossibleDamaged harness between the modules on Bus D
- RareA module on Bus D restarting because of weak supply
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.