OBD-II code · Powertrain (generic)
P02CB Turbocharger/Supercharger B Underboost Condition
Boost pressure on the secondary turbocharger/supercharger (B) is below the lower threshold. Wastegate stuck open, charge-air leak, or VGT vanes stuck open.
Is it safe to drive with P02CB?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyWastegate stuck open
- PossibleCharge-air pipe leak
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
- 1–6 h
- Emissions test
- Likely to fail
- Parts involved
- Turbocharger B, Wastegate B, Charge Air Pipe
Related codes
- P02CATurbocharger/Supercharger B Overboost Condition
- P02C8Cylinder 12 - Injector Restricted
- P02C9Cylinder 12 - Injector Leaking
- P02CCCylinder 1 Fuel Injector A Offset Learning At Min Limit
- P02CDCylinder 1 Fuel Injector A Offset Learning At Max Limit
- P02CECylinder 2 Fuel Injector A Offset Learning At Min Limit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.