4 Symptoms of a Faulty Wastegate
Turbochargers promise strong performance, but when the internal wastegate fails, that performance suffers. Learn the typical symptoms of a faulty turbocharger wastegate (some of which can be quite alarming), what causes it, and how much it costs to repair or replace a wastegate.
What is a turbo wastegate?
The turbo wastegate is a vital component found under the hood of any turbocharged vehicle.
It is used to regulate the maximum turbine speed of the turbocharger, thereby controlling the overall boost pressure production. This significantly reduces the chances of an overcharging condition occurring in the engine’s turbocharging system.
How a wastegate works
To better understand the process described above, we must first have a good understanding of the basic principles of how a turbocharger works. A turbocharger uses exhaust energy generated during the combustion process to drive a special turbine wheel, which forces compressed air into the engine’s intake tract.
This oxygen-rich intake air is ideal for more volatile combustion, especially when additional fuel is supplied to each cylinder.
A wastegate regulates the turbocharger’s turbine speed by diverting excess exhaust energy away from the engine’s turbo under certain conditions. Simply put, the maximum energy applied to the control (exhaust) side of the turbocharger impeller shaft is effectively limited by the corresponding wastegate, keeping peak boost pressure under control.
Turbo wastegates come in a variety of shapes and can be located internally or externally depending on the application. Either way, most turbocharger wastegates contain a spring/diaphragm assembly that is acted upon by compressed air that is distributed through an attached sensor line.
Here is a great video on how internal and external wastegates work.
Recognizing such symptoms can prove invaluable in expediting the repair of the problem at hand. Below are some of the most common symptoms associated with a faulty wastegate.
1) Check Engine Light Illuminated
Most of the time, wastegate-related issues will cause your vehicle’s check engine light to illuminate. This is because the engine is unable to achieve the required manifold pressure while in operation.
You will need to use an OBD2 diagnostic tool to check for specific diagnostic trouble codes (DTCs) stored in your vehicle’s ECM to see if it’s a wastegate issue. Examples of wastegate-related codes include P0234, P0243, P0244, P0245, and P0250.
2) Insufficient boost pressure
When the turbo wastegate is stuck open, exhaust gases are forced out the engine without passing through the turbo exhaust side. This causes a significant drop in boost pressure.
3) Reduced fuel consumption
Furthermore, when the wastegate is stuck open, too much fuel is burned to achieve the desired engine performance. However, this desired performance is never achieved due to an insufficient intake air supply.
4) Abnormal boost pressure
When the turbo wastegate is stuck closed, the risk of engine overboost increases significantly. This often results in the boost pressure indicator being inaccurate or too high – if this condition is not corrected immediately, serious damage to the engine can occur.
