P2B81Wastegate Position Sensor A Circuit Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2B81 reports that electric wastegate A does not behave as commanded although its sensor signal is electrically fine. GM documents it for the 2.7L L3B (table 19OBDG03D): with the actuator in normal operation the fault counts if the position error exceeds 20 % for over 1 s, actuator current exceeds 1.0 A for over 1 s or duty cycle exceeds 40 % for over 1 s, and 25 of 30 samples must fail; the 2025 table 25OBDG03B tightens the position limit to 10 % for 2 s with 29 of 30. It is Type A, so the MIL comes on in the first trip. GM bulletin PIP6007A names increased friction in the wastegate valve on the 2.0L LSY (Blazer, XT4 to XT6, CT4, CT5, Envision) and calls for turbocharger replacement. Wiring faults set P2AB7 to P2AB9.
- What you may notice
- MIL in the first trip
- Boost too low or too high, flat or jerky acceleration
- Reduced power mode possible
- Likely causes
- LikelyWastegate valve or linkage binding (GM PIP6007A, turbo replacement)
- PossibleElectric wastegate actuator worn or drawing excessive current
- RareLinkage clip missing or rod detached
- 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: €150 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.