P0299
Turbocharger/Supercharger Underboost
Quick answer: P0299 means turbocharger/Supercharger Underboost. Fixing the underlying cause typically runs $260 to $2,600 at an independent shop. Drive gently, service soon.
- Severity
- Moderate
- Safe to drive?
- Drive gently, service soon
- Typical repair
- $260 to $2,600
- Most likely cause
- A split, loose, or disconnected charge pipe or intercooler boost hose (the most common cause and the cheapest fix)
What P0299 means
The computer commanded a certain amount of boost pressure and measured meaningfully less than it asked for. On turbocharged engines the pressurized air travels through a chain of pipes, intercooler, and valves, and a leak or lazy actuator anywhere along that chain shows up as underboost. The very common and very cheap version of this code is a boost hose that has popped off or split, which is why a visual inspection comes before any talk of a new turbo.
Common symptoms
What drivers usually notice with this code.
- Noticeably down on power, especially when accelerating or climbing
- Limp mode with reduced power after harder acceleration
- A hissing or whooshing sound under boost (often the leak itself)
- Slightly worse fuel economy
- Sometimes a whistle that has changed pitch, or smoke if the turbo itself is failing
Common causes
Ranked from most to least likely.
- 1A split, loose, or disconnected charge pipe or intercooler boost hose (the most common cause and the cheapest fix)
- 2A stuck or failing wastegate or its actuator bleeding boost off early
- 3A faulty boost-control solenoid or a cracked vacuum line to it
- 4A boost pressure sensor reading wrong, so real boost gets reported as low
- 5A clogged air filter or restricted intake or exhaust limiting what the turbo can build
- 6A worn turbocharger with shaft play or damaged vanes (the expensive end, often with oil consumption or smoke as a clue)
Can I keep driving?
Usually yes, since most cars respond by limiting boost and feeling slow rather than breaking, but keep driving gentle, because if the cause is an oil-starved turbo, pushing it can turn a hose repair into a turbo replacement.
Severity: Moderate. A flashing check-engine light always means stop, whatever the code says.
Ballpark cost
What P0299 usually costs to fix
A range, not a quote. What you pay depends on your vehicle, your area, and which of the causes above turns out to be the real one.
Typical parts and labor at an independent shop. Dealer rates run higher.
That spread is wide on purpose. P0299 points at a system, not a single part, so the real answer depends on what the diagnosis finds. Use the range to know what to expect. If an estimate comes in higher, it usually means the specific repair is more involved, and it is always fair to ask what is included.
Next steps
What to do next
Ask the shop to pressure-test the charge system first, which is the boost-side equivalent of a smoke test and finds leaks fast. The repair bill hinges entirely on where in the chain the problem sits: a clamp or hose is cheap, a wastegate actuator is moderate, and a turbo replacement is the expensive outcome that deserves a confirmed diagnosis, not a hunch. If a turbo is being recommended, ask what evidence points to it, such as shaft play or oil in the intake tract, before you commit to that scale of repair.
Walk in informed
Ask for the diagnosis in writing and which test confirmed it, so you understand exactly what is being fixed. Fixxr shows you what the job typically costs near you, so you can approve the work with confidence.
Sources & further reading
- NHTSA — Check for vehicle safety recalls — look up open recalls for your vehicle by VIN, free
- FTC — Auto repair basics — your consumer rights at the repair shop
- AAA — Car repair and maintenance costs — independent guidance on what repairs should cost
Cost ranges and guidance reviewed July 2026.
P0299 FAQ
P0299 questions, answered
Can I drive with a P0299 code?
Usually yes, since most cars respond by limiting boost and feeling slow rather than breaking, but keep driving gentle, because if the cause is an oil-starved turbo, pushing it can turn a hose repair into a turbo replacement.What does the P0299 code mean?
The computer commanded a certain amount of boost pressure and measured meaningfully less than it asked for. On turbocharged engines the pressurized air travels through a chain of pipes, intercooler, and valves, and a leak or lazy actuator anywhere along that chain shows up as underboost. The very common and very cheap version of this code is a boost hose that has popped off or split, which is why a visual inspection comes before any talk of a new turbo.What are the most common causes of a P0299 code?
The most likely causes, roughly in order, are a split, loose, or disconnected charge pipe or intercooler boost hose (the most common cause and the cheapest fix); a stuck or failing wastegate or its actuator bleeding boost off early; a faulty boost-control solenoid or a cracked vacuum line to it; a boost pressure sensor reading wrong, so real boost gets reported as low. Ask the shop to pressure-test the charge system first, which is the boost-side equivalent of a smoke test and finds leaks fast. The repair bill hinges entirely on where in the chain the problem sits: a clamp or hose is cheap, a wastegate actuator is moderate, and a turbo replacement is the expensive outcome that deserves a confirmed diagnosis, not a hunch. If a turbo is being recommended, ask what evidence points to it, such as shaft play or oil in the intake tract, before you commit to that scale of repair.How much does it cost to fix a P0299 code?
Fixing the underlying problem behind a P0299 code typically runs $260 to $2,600 at an independent shop, including parts and labor. The exact figure depends on your vehicle and which part turns out to be at fault.
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