The most common causes are: Boost leak — cracked intercooler pipe or loose clamp (very common); Failed or leaking intercooler; Stuck wastegate held open; Failed wastegate actuator or boost control solenoid; Carbon buildup on variable-geometry turbo vanes.

How much does it cost to fix P0299?

Typical repairs range from $30–$200 for replace clamp or coupler up to $1,200–$3,500 for replace turbocharger. Costs vary by vehicle and region.

P0299powertrain

P0299 – Turbocharger/Supercharger Underboost Condition

What does P0299 mean?

The turbocharger or supercharger is producing less boost pressure than the computer commanded — an underboost condition. The engine is not making the power it should, usually because boost is leaking out or the turbo cannot spool properly.

What causes P0299?

Listed from most to least common:

1Boost leak — cracked intercooler pipe or loose clamp (very common)
2Failed or leaking intercooler
3Stuck wastegate held open
4Failed wastegate actuator or boost control solenoid
5Carbon buildup on variable-geometry turbo vanes
6Clogged air filter or restricted intake
7Failing turbocharger with worn bearings
8Restricted exhaust or clogged diesel particulate filter

Code breakdown

SystemP — Powertrain

TypeGeneric (standardized SAE / OBD-II code — same meaning across most manufacturers)

SubsystemFuel and air metering (injector circuit)

Common symptoms

Check engine light on
Noticeable loss of power, especially under acceleration
Vehicle may enter limp mode
Hissing sound from a boost leak
Black smoke on diesels
Poor fuel economy

How to diagnose

1Perform a boost leak test by pressurizing the intake system and listening for escaping air. This is the fastest way to find the common causes.
2Inspect all intercooler pipes, couplers, and clamps — these loosen and crack over time.
3Check the air filter and intake for restriction.
4Test the wastegate actuator and boost solenoid.
5Compare commanded vs actual boost in live data under load.
6On VGT turbos, inspect the vane mechanism for carbon seizing.
7Check for exhaust restriction, including DPF condition on diesels.

Not immediately damaging, but it indicates a leak or turbo problem that will worsen. Significant power loss can also be a hazard when merging or overtaking.

Common fixes and estimated costs

Repair	Estimated cost
Replace clamp or coupler	$30–$200
Replace intercooler pipe	$100–$400
Clean VGT vane mechanism	$300–$900
Replace boost solenoid or actuator	$200–$800
Replace turbocharger	$1,200–$3,500

Costs are rough US estimates including parts and labor. Actual pricing varies significantly by vehicle, region, and shop rates.

Good to know

Start with a boost leak test before considering turbo replacement. A split coupler or loose clamp produces the exact same code and symptoms as a failing turbo, and costs a fraction to fix.

Back to all Powertrain Codes →

This information is provided for general reference only and may vary by manufacturer, model, and year. It is not a substitute for professional diagnosis or repair.