U0297Lost Communication With AC/DC Converter Control Module B
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Converter B is a second AC/DC unit, typically an additional on-board charger that raises AC charging power when combined with the first. Patents show how such pairs are coordinated: in Porsche's US10029578B2 one charger leads and the other follows commands received over a communication link, while Hyundai's US10270273B2 has a master controller steering slave controllers for several power modules. U0297 is stored when the controlling module no longer hears unit B. The vehicle usually continues to charge with converter A alone, but at a lower rate. Because CARB wants plug-in hybrid OBD to catch charger problems that reduce charging speed, a silent B is relevant there too. No manufacturer documents U0297 publicly; Volvo's use of U0296 concerns unit A.
- What you may notice
- AC charging noticeably slower than usual
- Charging system warning
- Likely causes
- PossibleLow-voltage supply or wake-up line of charger B missing
- PossibleCommunication line between the converters interrupted
- PossibleSoftware or configuration does not match the fitted charger variant
- RareConverter B internally failed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.