P2BBBTurbocharger/Supercharger Bypass Valve A Position Sensor Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2BBB is the general fault of the position feedback from bypass valve A, the electrically driven valve that lets boosted air flow back from the compressor outlet to its inlet when the throttle closes or boost has to be trimmed. It is not the wastegate on the exhaust side. The engine module reads the sensor as a share of its 5 V reference; this code covers an open line or a signal it cannot sort into low or high. GM's 2019 tables for the supercharged 6.2-litre LT5 (Corvette ZR1) watch this sensor but publish only the low and high codes P2BBC and P2BBD; no manufacturer documents P2BBB itself publicly. An Achates Power patent explains why the feedback matters: without a valid position the commanded opening cannot be verified and boost control loses accuracy. Expect a warning light and reduced boost.
- What you may notice
- Check engine light
- Reduced boost and noticeably less power
- Whoosh or flutter noise when lifting off the throttle
- Likely causes
- LikelyLoose, corroded or unplugged connector at the bypass valve position sensor
- PossibleChafed or broken signal, reference or ground wire in the harness near the compressor
- PossibleInternal fault of the position sensor in the valve actuator
- RareFaulty sensor input or 5 V reference inside the engine control 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: €60 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.