P2BF8Exhaust Flow Control Valve B Control Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Valve B is the second exhaust flap; Ford's gasoline OBD summaries 2020-2024 put it on bank 2, while valve A (P26C5) serves bank 1. P2BF8 reports that the drive circuit for flap B is open or unusable. On Ford a smart driver checks the output continuously and flags it within about 5 seconds; the 2024 summary files the open circuit as subtype 13. GM's 2023 and 2024 OBD tables (23OBDG07, 24OBDG07) watch the PWM control line of an exhaust valve the same way: open circuit, battery above 9 V, 4 seconds, two trips to the MIL. Ford names P2BF8 in its Mustang active exhaust bulletins, and 25-2144 for F-150 trucks with the 5.2 L engine, model years 2023 to 2025, lists P2BF8:78, an actuator that fails alignment, which a PCM update and relearn resolve. A broken wire or unplugged actuator is the usual find.
- What you may notice
- Check engine light on
- Exhaust mode not available message
- One tailpipe flap no longer moves
- Likely causes
- LikelyBroken or unplugged harness to the bank 2 flap actuator
- PossibleOpen circuit inside the flap actuator
- PossibleActuator not aligned after replacement or outdated PCM software (subtype 78)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.