P2BF9
Exhaust Flow Control Valve B Control Circuit Low
The exhaust flow control valve B reports a control circuit low condition. Exhaust routing for back-pressure or noise control cannot be commanded reliably.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Control wire shorted to groundCommon
- Internal short in actuator coilPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Exhaust Flow Control Valve B
- Wiring Harness
- ECM
P2BF9 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.