P0299 is the generic OBD-II code for a turbocharger or supercharger underboost condition. It means the engine is making less boost than the engine computer expects. As of November 4, 2026, the causes below are the usual suspects, and the cost ranges come from one repair reference.
The code does not name a failed part, so the cheapest checks come first. Start with the intake and boost piping, then the sensor and wastegate, before anyone replaces a turbo.
This article is general information, not a repair manual. Because boost faults can damage the engine, have a qualified technician confirm the cause on your vehicle.
What the P0299 code means
P0299 is the generic OBD-II code for turbocharger or supercharger underboost, set when boost pressure stays below the level the engine computer expects. The full name used in repair references is Turbocharger/Supercharger A Underboost Condition.
The P0 prefix means the code is generic, so the basic meaning of P0299 is the same across makes and models. The engine control module watches intake pressure, and it stores the code when pressure stays out of range. The code reports a result, not a cause, so the fault can sit in several places.
Low boost means the turbo or supercharger is not forcing enough air into the engine. Less air means less power, and the check engine light often comes on with it.
Common causes of P0299
The most common causes of P0299 are air or boost leaks, a faulty boost pressure sensor, a wastegate or boost regulator fault, and a failing turbo or supercharger. Repair references list several others as well.
- Air intake leaks or restrictions
- Boost pipe leaks at hoses, clamps or connections
- A faulty turbo or supercharger
- A faulty boost pressure sensor
- A malfunctioning wastegate or boost regulator
- A faulty EGR system on some turbo engines
- Low engine oil pressure, which can starve the turbo of lubrication
A single component can also set the code. The Audi bulletin on P0299 for 2005 to 2007 A3 and A4 models says the condition may result from an abnormal turbocharger recirculation valve, so a torn valve membrane is one case to check.
KBB’s code guide also flags low oil pressure as a root cause. It says that low oil starves the turbo of lubrication, which can make the internal turbo bearings fail. Low power on a turbo engine can also come from fuel delivery, and the fuel rail pressure low code P0087 explains that case.
Symptoms to watch for
A P0299 usually shows a check engine light and a noticeable loss of engine power. Some cars also enter limp mode or make noise from the turbo or supercharger area.
- Check engine light, the most common sign
- Reduced engine power and slow acceleration
- Limp mode, where the car limits its own power
- Noise from the area around the turbo or supercharger
One repair reference says that if the car enters limp mode, you can only drive a short distance before repairing it. Treat limp mode as a clear sign to stop driving and call a technician. A separate reduced engine power message guide explains that warning.
Is it safe to keep driving?
Repair guides warn that driving with a failed turbo or supercharger can cause permanent engine damage, so a P0299 should be inspected promptly. The sources do not agree on how long a car can keep running with the code, so do not rely on a general rule.
KBB’s P0299 guide makes the same warning, saying that driving with a failed turbocharger can result in costly engine damage. It advises seeing a qualified mechanic as soon as possible, especially when the turbo has failed.
Low oil pressure is one of the listed causes, and the same references note that low oil can starve the turbo bearings. If you see reduced power, unusual noise or limp mode, park the car safely and have it inspected before a long trip.
How to diagnose P0299 step by step
Start by scanning for related codes and reading the freeze-frame data, then check for leaks before you replace a turbo or sensor. The order below follows a common repair reference, and it saves parts money when the fault turns out to be a leak.
- Scan for codes, address any related codes first, and read the freeze-frame data to see what the turbo was doing when the code set.
- Clear the codes, then test drive the car to see whether P0299 returns.
- Have someone rev the engine while you listen for whistling from the boost pipes.
- Visually inspect the turbo or supercharger, the EGR system and the air intake.
- Read the boost pressure sensor with a scan tool and compare it with the expected values.
- Check the wastegate arm for sticking, and use a vacuum or air pressure tool on vacuum-operated wastegates.
- Check engine oil pressure, then the intake for leaks or blockages.
Check for leaks first
Leaks are a practical first target because they are cheap to find and cheap to fix compared with a turbo. A smoke test shows where intake air escapes, and a boost pipe leak can often be heard as whistling under load. A leak that lets in unmetered air can also set lean codes, as described in lean mixture code causes.
Test the wastegate and sensor
A stuck wastegate arm or a weak boost sensor can set the code even when the turbo itself is sound. Check both before you accept a turbo replacement as the only fix.
For a concrete example, Audi’s Audi technical service bulletin for the 2.0 TFSI engine lists the repair: remove the turbocharger recirculation valve, inspect its rubber membrane, and replace the valve if the membrane is torn. The bulletin applies only to those 2005 to 2007 models, so it does not cover other cars.
How much does it cost to fix P0299?
Repair estimates for P0299 range from about $75 for low oil pressure work to $2,500 to $3,500 for a supercharger replacement, as of November 4, 2026. These are one repair reference’s parts and labor estimates, not a quote for your car. If the low pressure reading turns out to be a faulty sensor rather than the engine, oil pressure sensor price and labor time gives the cost range.
| Repair | Estimated cost (parts and labor) |
|---|---|
| Boost pipe leak repair | $0 to $200 |
| Repair low engine oil pressure | $75 to $250 |
| Replace boost pressure sensor | $150 to $200 |
| Air intake repair | $250 to $600 |
| EGR valve replacement | $350 to $500 |
| Replace turbocharger | $1,500 to $2,500 |
| Replace supercharger | $2,500 to $3,500 |
Prices change with the vehicle, the region and the shop, so treat these ranges as a starting point and ask for a written estimate. A leak repair costs far less than a turbo, which is why checking for one first can save money.
Common mistakes when fixing P0299
The most common mistake is clearing the code and replacing parts before testing, because a fault that is still present will set P0299 again. Skipping the basic checks is the costliest habit.
- Replacing the turbo before checking boost pipes and clamps
- Clearing the code without reading the freeze-frame data
- Replacing a boost sensor without reading its live values first
- Ignoring low oil pressure, which can damage turbo bearings
- Assuming the same fix applies to every make, since procedures differ by manufacturer
Frequently Asked Questions
Can I clear a P0299 code myself?
Yes, a scan tool can clear a stored code, but clearing it does not repair anything. Repair guides say the code can return after a test drive if the cause is still present. Check for leaks and related codes first, then clear the code and confirm the result on a test drive.
Does P0299 always mean the turbo is bad?
No. Repair references list leaks, boost sensors, wastegate faults, EGR problems and low oil pressure as causes, alongside a failing turbo or supercharger. A technician should test the cheaper items before condemning the turbo, because several of the causes cost much less to repair.
Is P0299 the same on every car?
The P0 prefix marks it as a generic code used across makes, so the meaning is the same. The causes and test procedures can differ by manufacturer. One repair reference notes that the code can point to a wastegate bypass valve on Volkswagen or to a VGT actuator on Ford, so follow the service information for your exact vehicle.
Can a torn recirculation valve cause P0299?
In some cases, yes. The Audi bulletin says the condition may result from an abnormal turbocharger recirculation valve, and its service calls for replacing the valve when the rubber membrane is torn. That bulletin covers 2005 to 2007 A3 and A4 models with the 2.0 TFSI engine, so check whether it applies to your car.
What are the early warning signs of a boost problem?
The check engine light is the most common first sign, and reduced power often follows. Some cars enter limp mode, and a failing turbo or supercharger can make noise from its area. If you notice any of these, ease off the throttle and get the car checked soon.
If the check engine light shows P0299, book a technician to confirm the cause before buying parts. Ask for the leak and sensor checks first, and request a written estimate, because the ranges above come from one source and can differ in your area.
