OBD-II code · Powertrain (generic, extended)
P2CB8 Turbocharger/Supercharger Boost Pressure B Too High – Mechanical
The boost pressure on branch B exceeds the calibrated maximum. Mechanical fault — wastegate stuck closed or boost control valve jammed.
Is it safe to drive with P2CB8?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyWastegate stuck closed
- PossibleBoost control valve jammed
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 2–12 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Turbocharger B, Wastegate B, Boost Pressure Sensor B
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.