P2BF6Exhaust Flow Control Valve A Position Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2BF6 means the position feedback of exhaust valve A sits below its valid range, as with a signal shorted to ground or a lost sensor supply. Mazda is the best documented user: its 2.5 litre Skyactiv-G with cylinder deactivation carries an exhaust shutter valve that Mazda patents describe as closing partly in two-cylinder mode to damp exhaust pulsation noise. Bulletin 01-004/20 calls P2BF6:00 a shutter valve position sensor low input detected within one drive cycle and reports the master warning light plus reduced power on 2019-2020 Mazda3 and 2020 CX-30; the cause was faulty PCM logic, cured by reprogramming. Mexican-market cars without deactivation are excluded. Deutz uses the same code on MD1 engines when the flap voltage drops under its normal band. Wiring and sensor must still be checked.
- What you may notice
- Master warning or check engine light on
- Reduced engine power
- Likely causes
- LikelyPCM software misjudging the sensor (Mazda bulletin 01-004/20)
- PossiblePosition signal wire shorted to ground
- PossibleSensor supply open or connector not latched
- RarePosition sensor in the shutter valve failed
- 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: €0 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.