P0049: Turbocharger/Supercharger A Turbine Overspeed
Do not keep driving
Stop driving. This is a code to have the vehicle recovered on, not driven in. The failure it warns about damages the engine, not just the turbocharger.
What this code means
The turbocharger has been spinning faster than its design limit. A compressor wheel that lets go at these speeds does so violently, and the debris goes straight into the engine. The usual chain of events is a boost control fault that lets the wastegate stay shut, or a leak downstream that lets the compressor spin freely without building pressure — so the overspeed is nearly always a symptom of something else that must be found before the engine is used again.
Likely causes
Start here
- Failed boost control solenoid · moderate
- Faulty wastegate actuator · moderate
- Boost leak in charge pipework · moderate
Less common
- Seized variable geometry turbocharger vanes · specialist
- Aftermarket engine tuning beyond design limits · specialist
- Faulty boost pressure sensor · moderate
Symptoms
Components involved
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.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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