P2BBDTurbocharger/Supercharger Bypass Valve A Position Sensor Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2BBD is the high-side counterpart: the position signal from bypass valve A rises toward the full reference voltage. That points to a short to the 5 V supply or to battery voltage, a broken sensor ground – the signal then floats upward – or a defective sensor. On GM's 2019 Corvette ZR1 with the LT5 V8 the module flags a raw position reading above 95 % of reference in 10 out of 14 samples at 100 ms intervals, with at least 11 V on the powertrain relay and outside of cranking; Type A, so the MIL lights at once. P2BBC covers the low side and P2BBB a general circuit fault of the same sensor. With the reading implausible, the module usually holds the valve in a safe position and reduces boost, so the car feels flat and may make noise when the throttle snaps shut.
- What you may notice
- Check engine light on immediately
- Reduced power because boost is limited
- Unusual noise when lifting off the throttle
- Likely causes
- LikelyOpen sensor ground wire or corroded ground terminal
- PossibleSignal wire shorted to the 5 V reference or to battery voltage
- PossibleDefective position sensor in the valve actuator
- RareMoisture in the valve connector creating a leakage path
- 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: €60 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.