Cause
Faulty wastegate actuator
The actuator opening the wastegate to limit boost. Frequently a separate part from the turbocharger and easy never to discover that, so it belongs at the top of any over- or underboost list. Stuck shut overboosts and triggers a protective cut; stuck open gives no boost at all.
It needs calibrating after replacement on many vehicles — skip that and the same code returns on a new part.
Typically a moderate job.
Some of these codes mean you should stop driving
2 of the 9 codes this can cause indicate a fault where continuing to drive risks damage or is unsafe. Which one you have matters more than the cause does — read the code's own page before deciding.
Codes this can cause (9)
Codes where this is a likely explanation first, rather than merely a possible one.
- P0049 Turbocharger/Supercharger A Turbine Overspeed Likely for this code Stop driving Critical
- P0234 Turbocharger/Supercharger A Overboost Condition Likely for this code Stop driving High
- P0244 Turbocharger/Supercharger Wastegate Actuator A Range/Performance Likely for this code High
- P0248 Turbocharger/Supercharger Wastegate Actuator B Range/Performance Likely for this code High
- P0299 Turbocharger/Supercharger A Underboost Condition Likely for this code High
- P0046 Turbocharger/Supercharger Boost Control A Circuit Range/Performance High
- P0236 Turbocharger/Supercharger Boost Sensor A Circuit Range/Performance High
- P0240 Turbocharger/Supercharger Boost Sensor B Circuit Range/Performance High
- P2B94 Wastegate Position Sensor B Exceeded Learning Limit Moderate
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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