U02B0Lost Communication With Turbocharger/Supercharger Boost Control B Position Sensor
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- This code covers the digital position feedback of the second boost actuator. Its A counterpart, U0656, appears in GM's 2025 engine tables: the ECM reads the vane position as SENT frames and fails the link when frames stop updating for more than 6.25 ms while the line sits steadily low or high, or when message errors pile up, 480 failures in 600 samples, rated Type A (lamp on the first trip). No manufacturer documents U02B0 publicly; it applies wherever actuator B, for example on a second stage or bank, has its own sensor of this kind. Without feedback the controller can no longer hold that actuator in closed loop and falls back to a safe setting. Analog sensors use P2586 to P2590. Expect the MIL and less power.
- What you may notice
- Check engine lamp on the first trip
- Reduced power, boost no longer regulated by actuator B
- Higher smoke or emissions on diesel engines
- Likely causes
- LikelySignal line or connector of the B position sensor damaged or corroded
- PossiblePosition sensor of actuator B failed (often integrated in the actuator)
- Possible5 V reference or ground of the sensor missing
- RareEngine controller input damaged
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €50 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.