What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer communications
2Original wording in English
POLESTAR
Reported code forms B109A4A
This is a Technical Journal: DTC CEM B109A4A Incorrect BBS. This DTC is not valid, and it does not affect the function. Erase the DTC and release the vehicle back to the customer. A SW solution is planned during 2025…
VOLVO
Reported code forms B109A4A
This is a Technical Journal: DTC CEM B109A4A Incorrect BBS. A SW solution is planned during 2025 quarter 4.
Check vehicle applicability
34A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Polestar | POLESTAR 2 | 2026 |
| Polestar | POLESTAR 2 | 2025 |
| Volvo | C40BEV | 2025 |
| Volvo | EC40 | 2026 |
| Volvo | EC40 | 2025 |
| Volvo | EX40 | 2025 |
| Volvo | S60MHEV | 2025 |
| Volvo | S60PHEV | 2025 |
| Volvo | S90MHEV | 2026 |
| Volvo | S90MHEV | 2025 |
| Volvo | S90PHEV | 2026 |
| Volvo | S90PHEV | 2025 |
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.