P0299: Turbocharger/Supercharger A Underboost Condition

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Symptoms of an Error Code P0299

This error code is sent when your bank A is not providing enough pressure. A turbocharger or supercharger works by creating a pressurized airstream that goes into your engine. The additional pressure of the air is what allows your engine to produce more power than typical of an engine its size.

Turbochargers drive from the exhaust exiting your engine and utilize a turbine that forces air into the intake. On the other hand, superchargers are installed underneath the intake side of your engine and often use an engine belt to force additional air into your intake. This means that the issue could be on either the exhaust or intake end of your engine, depending on whether you have a supercharger or a turbocharger. Additionally, manufacturers use a different turbochargers or superchargers, so this repair can be dependent on your particular make of vehicle.

Depending on the severity of the issue, you could experience a range of symptoms. A moderate decrease in pressure will be unnoticed except for your malfunction indicator lamp being illuminated. More severe issues can dramatically reduce the power of your engine and may create unusual sounds during normal operation.

Typical Causes

Whether you experience these symptoms or not, here are some typical causes of an error code P0299 problem. Typically, this code is the result of an air restriction or leak in the intake of your engine. Another common cause is a binding turbocharger or simply a faulty pressure sensor.

Depending on the make of your vehicle, here are some other causes. Check out your specific service manual for more information:

If possible, find out the specific cause before moving on to solutions. The integral nature of your turbocharger or supercharger mean that you may have other DTC codes present, so troubleshoot these other codes before looking at error code P0299. As with many error codes, an issue with your engine air pressure could affect a whole range of sensors and systems and cause other error codes to trip.

How to Fix P0299

Once you’ve solved other error codes, you’ll need to inspect your entire intake air system for any missing, damaged, or loose parts that would break the seal and cause you to lose pressure. A crack, clog, or loose connection in the system is the most common issue that would trigger trouble code P0299.

After you’ve completed a visual inspection, you’ll need to check out your turbocharger wastegate regulating valve solenoid, diverter valve and any regulators and sensors that work with the pressure of your turbocharger or supercharger.

If your vehicle still has a pressure issue, check out the latest Technical Service Bulletins, or TSBs. These detail common issues for your specific trouble code and the make and model of your vehicle. Each turbocharger and supercharger system is highly unique, so less common solutions will be dependent on your specific system.

Now that you’ve troubleshooted your P0299 code, you know what the code P0299 means. While these causes and solutions are common for this code, check out your specific make and model vehicle repair manual to determine the source of the issue if you’re still having pressure and performance issues with your turbocharger or supercharger.

If the job is too big for you, seek out one of our Preferred Shops to help you do the job.