The control module has detected that turbocharger A runs above its permitted maximum speed. Engines equipped for it measure turbine speed with a dedicated sensor on the shaft; while the fault is active some systems continue with an estimated speed and reduce power. Real overspeed arises when too much exhaust energy reaches the turbine, for example because the wastegate or the turbine vanes stick closed, or because the turbocharger has to compensate for a charge-air leak or high altitude. Since a damaged turbocharger can fail completely, the cause should be found before driving on. Turbocharger B has its own code.
Medium severity. Can I keep driving?Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.
Symptoms
- Check engine light on
- Reduced power or limp mode
- Whistling from the turbocharger
- Risk of turbocharger damage
Most likely causes
- Wastegate or turbine vanes stuck closed, boost control fails
- Turbocharger speed sensor or its wiring faulty
- Charge-air leak forcing the turbocharger to higher speed
- Engine control module or software
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- It can trigger limp mode.
- It affects emissions.
What each character of P0049 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 0: Subsystem depends on the code range
- 49: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0049?
Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.
What causes code P0049?
The most common causes are: wastegate or turbine vanes stuck closed, boost control fails; turbocharger speed sensor or its wiring faulty; charge-air leak forcing the turbocharger to higher speed.
Related codes
- P00C5Turbocharger/Supercharger B Turbine Overspeed
- P2579Turbocharger/Supercharger Speed Sensor A Circuit Range/Performance
- P0234Turbocharger/Supercharger A Overboost Condition
- P0243Turbocharger/Supercharger Wastegate Actuator A
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.