P0299 Turbocharger/Supercharger Underboost Condition
P0299 is a generic OBD2 powertrain code. It means “Turbocharger/Supercharger Underboost Condition” — the same on every make and model, because the definition comes from the SAE J2012 standard rather than from the carmaker.
Ask the AI about P0299 on your car- System
- Powertrain (P)
- Code type
- Generic (SAE)
- Range
- P02xx
- Urgency
- Moderate
What P0299 means
The turbocharger (or supercharger) isn’t delivering the boost pressure the computer asked for.
Symptoms
- A noticeable loss of power
- Limp mode
- Whistling or hissing under acceleration — a boost leak
- Black smoke on diesels
Most likely causes
- A boost leak — a split intercooler hose or a loose clamp — the most common
- A wastegate stuck open, or its actuator or solenoid failing
- Sticking variable vanes on a diesel turbo (soot)
- A worn turbocharger
- A clogged air filter or a faulty boost-pressure sensor
What to check first
- Inspect every intercooler hose and clamp — an oily film on a hose often marks the leak
- Check that the wastegate or vane actuator moves freely
- With the engine off, the boost sensor should read the same as atmospheric pressure
Can I keep driving with P0299?
Drivable — plan the repair soon
Yes, gently — avoid full throttle until it’s fixed. If the turbo itself is noisy or smoking, stop: a failing turbo can starve itself of oil and fail completely.
How P0299 breaks down
Powertrain. Engine, transmission, fuel and emissions — the codes behind the check engine lamp.
Generic code: defined by SAE, the same on every make.
Fuel & air metering.
The specific fault within this range.
Where to look: Fuel & air metering
The sensors the engine computer meters fuel from — mass air flow, manifold pressure, intake air and coolant temperature, throttle position, oxygen sensors and fuel pressure — the fuel trims it learns from them, and the injector, fuel-pump and turbocharger circuits.
All P02xx codes →Ask the AI about P0299 on your car
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Read and clear P0299 on your iPhone
Brimly reads stored, pending and permanent codes through a Bluetooth LE or Wi-Fi OBD2 adapter, explains each one offline from the same 2,693-code dictionary as this page, and clears them once the fault is fixed — each clear goes into the car’s service history with the codes it removed. OBD diagnostics are part of Brimly Forever, a one-time purchase; the PRO assistant explains a code for your exact car.
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Frequently asked
What does P0299 mean?
P0299 is a generic OBD2 powertrain code. It means “Turbocharger/Supercharger Underboost Condition” — the same on every make and model, because the definition comes from the SAE J2012 standard rather than from the carmaker. The turbocharger (or supercharger) isn’t delivering the boost pressure the computer asked for.
Can I drive with P0299?
Yes, gently — avoid full throttle until it’s fixed. If the turbo itself is noisy or smoking, stop: a failing turbo can starve itself of oil and fail completely.
What causes P0299?
A boost leak — a split intercooler hose or a loose clamp — the most common; A wastegate stuck open, or its actuator or solenoid failing; Sticking variable vanes on a diesel turbo (soot); A worn turbocharger; A clogged air filter or a faulty boost-pressure sensor.
How do I clear P0299?
Fix the cause first, then clear it with any OBD2 scanner or app. Once the fault is gone the car also clears it on its own: the check engine lamp goes off after the self-test passes on three drive cycles in a row, and the stored code ages out after about 40 warm-ups. Clearing without a repair only hides it for a while — and resets the readiness monitors an emissions inspection looks at.
Is P0299 the same on every car?
Yes. P0299 is a generic SAE J2012 code, so its definition is identical on every make and model. What differs is the cause behind it and the repair procedure, which depend on the engine — that’s why the assistant on this page asks for your car.
Guides
Definitions: the generic SAE J2012 codes from Brimly’s offline dictionary (data version 2026.09). Causes and advice are general guidance for all makes — the service information for your car has the last word.