P2BBFTurbocharger/Supercharger Bypass Valve A Supply Voltage 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
- P2BBF concerns the power side of bypass valve A rather than its position feedback. Electric recirculation valves are moved by a small DC motor fed through an H-bridge in the engine module, and the bridge chip itself flags when its supply drops too far. GM documents exactly this for the eCRV of the 2019 Corvette ZR1: the motor driver reports low voltage in 80 of 100 samples at 12.5 ms, with relay voltage at least 11 V and the engine not cranking; Type A, MIL at once. Data sheets for throttle-type H-bridges such as NXP's MC33926 show how such an output stage switches off below its undervoltage lockout and reports this on a status line. Causes are a weak feed, a poor module ground or connector, or an internal driver fault. Without drive power the valve stays where it last stopped.
- What you may notice
- Check engine light on immediately
- Valve no longer moves, boost limited or surging on lift-off
- Often accompanied by other low-voltage codes
- Likely causes
- LikelyHigh resistance in the engine module feed, fuse or ground connection
- PossibleWeak battery or charging fault causing voltage dips
- PossibleCorroded pins at the engine module or valve connector
- RareInternal fault of the H-bridge driver in the engine module
- 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: €40 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.