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.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Common causes
Ordered by how often each turns out to be the cause.
- Wastegate stuck openCommon
- Charge-air pipe leakPossible
Parts involved
- Turbocharger B
- Wastegate B
- Charge Air Pipe
P02CB is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.