The OBD2 code P0049 signifies “Turbo / Supercharger Turbine Overspeed,” indicating that the turbocharger or supercharger is spinning at a speed higher than what the manufacturer deems safe. This condition can lead to various issues, including loss of power during acceleration, erratic engine performance, and can trigger the malfunction indicator lamp (MIL).
This code is often accompanied by other codes such as P0299, which indicates a turbocharger underboost condition, suggesting a relationship between the two problems.
P0049 quick overview
Meaning | P0049: Turbo / Supercharger Turbine Overspeed |
Is it serious? | Yes, it is serious because it can lead to turbocharger damage or failure if not addressed. |
Possible causes | – Faulty turbocharger bypass valve – Exhaust leaks or restrictions – Binding wastegate operation and linkage – Malfunctioning turbocharger boost pressure sensor – Obstructions in the intake or exhaust system |
How to diagnose? | Inspect for exhaust leaks or restrictions that could affect turbo operation. Check wastegate operation and linkage for any signs of binding or malfunction. Test the turbocharger boost pressure sensor for accuracy and proper functioning. Verify the operation of the turbocharger bypass valve to ensure it’s regulating boost levels correctly. Ensure there are no obstructions in the intake or exhaust system that could impede airflow. |
P0049 Meaning
When your car shows a P0049 code, it means the turbo or supercharger is spinning way too fast. This is risky because it can cause serious damage to your car’s engine if it’s not fixed. The problem might be with a part called the bypass valve, which helps regulate how much air the turbo is using.
If this valve or other parts like the wastegate, which controls the turbo’s speed, aren’t working right, your car won’t perform well and could even lose power when you try to speed up. Mechanics will look for leaks, check if parts are stuck, and make sure everything’s talking to the computer correctly to solve the issue.

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How to fix P0049 – learn from mechanics
I looked into P0049 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Audi P0049
Vehicle information 2015 Audi A4 2.0T Quattro
Issue + repair history
- MIL lamp illuminated
- Vehicle experiencing loss of power during acceleration
- Code P0049: Turbo / Supercharger Turbine Overspeed
- Previous repair: Replaced turbo wastegate actuator
- Symptoms persist despite actuator replacement
Other OBD2 Codes + Test Results
- P0049: Turbo / Supercharger Turbine Overspeed
- P0299: Turbocharger Underboost Condition
Mechanic suggestions
- Inspect for exhaust leaks or restrictions
- Check wastegate operation and linkage for binding
- Test turbocharger boost pressure sensor
- Verify proper operation of the turbocharger bypass valve
- Ensure there are no obstructions in the intake or exhaust system
Final fix
- Discovered faulty turbocharger bypass valve
- Replaced bypass valve and cleared codes, resolving the issue
Case #2: Subaru P0049
Vehicle information 2013 Subaru WRX STI 2.5L Turbo
Issue + repair history
- Engine experiencing intermittent loss of power
- MIL lamp on continuously
- Code P0049: Turbo / Supercharger Turbine Overspeed
- Previous repair: Replaced turbocharger wastegate
- Symptoms persist despite wastegate replacement
Other OBD2 Codes + Test Results
- P0049: Turbo / Supercharger Turbine Overspeed
- P0299: Turbocharger Underboost Condition
Mechanic suggestions
- Inspect for exhaust leaks or restrictions
- Test wastegate actuator for proper operation
- Check turbocharger bypass valve for leaks or malfunctions
- Verify operation of the boost control solenoid
- Ensure proper calibration of the turbocharger wastegate
Final fix
- Discovered damaged wiring at the boost control solenoid connector
- Repaired wiring and cleared codes, resolving the issue
Case #3: P0049
Vehicle information 2016 BMW 328i 2.0L Turbo
Issue + repair history
- Engine performance feels erratic
- MIL lamp illuminated intermittently
- Code P0049: Turbo / Supercharger Turbine Overspeed
- Previous repair: Replaced turbocharger wastegate
- Symptoms persist despite wastegate replacement
Other OBD2 Codes + Test Results
- P0049: Turbo / Supercharger Turbine Overspeed
- P0299: Turbocharger Underboost Condition
Mechanic suggestions
- Inspect for exhaust leaks or restrictions
- Test wastegate actuator for proper operation
- Check turbocharger boost pressure sensor for faults
- Verify operation of the turbocharger bypass valve
- Ensure there are no obstructions in the intake or exhaust system
Final fix
- Discovered failed turbocharger bypass valve
- Replaced bypass valve and cleared codes, resolving the issue
How to diagnose P0049
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
Diagnostic Step | Explanation |
---|---|
Inspect for exhaust leaks or restrictions | Check the exhaust system for any leaks or blockages that could be causing the turbine to overspeed. |
Check wastegate operation and linkage | Ensure the wastegate and its linkage are moving freely and not causing the turbo to spin excessively fast. |
Test the turbocharger boost pressure sensor | Verify that the sensor is accurately measuring the turbo’s boost pressure. |
Verify the operation of the turbocharger bypass valve | Confirm that the bypass valve is functioning correctly to prevent the turbo from overspeeding. |
Ensure no obstructions in the intake or exhaust system | Look for any blockages that could restrict air flow to and from the turbocharger. |

Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts

Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)