P02CATurbocharger/Supercharger B Overboost Condition
- Generic OBD-II code · Powertrain
- 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
- Turbocharger B is a second, separately controlled turbo – on twin-turbo or two-stage systems, or one per bank. No manufacturer using the turbo B codes was found; twin-turbo engines such as GM's 3.0 V6 and Ford's 3.5 EcoBoost report boost faults under P0234/P0299 with a shared boost sensor, so the description follows CARB and the turbo A codes. P02CA means actual boost of turbo B stays above target although the control is already lowering it; for turbo A, GM petrol engines use 20–35 kPa, Ford EcoBoost more than 4 psi over 5 s. Boost is then limited.
- What you may notice
- Check engine light, reduced power, limp mode
- Power cut under load
- Possibly knocking (petrol)
- Likely causes
- LikelyWastegate B stuck closed, linkage seized
- PossibleBoost control valve or actuator B faulty, vacuum line swapped or leaking
- PossibleBoost sensor reading wrong
- PossibleTurbo B vanes sooted (diesel)
- RareSoftware or calibration, tuning
- 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 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.