P0299 on Buick
Turbo/Supercharger Underboost Condition
P0299 on Buick vehicles indicates turbo/supercharger underboost condition. Au7o has documented this code across 1 Buick model — most commonly on Encore. P0299 means the engine computer detected an underboost condition — the turbocharger or supercharger is producing less boost pressure than the PCM expects for the given conditions. The computer compares the manifold/boost pressure sensor reading to a target based on engine load, and when actual boost falls short, it sets this code. The most common real-world cause is a leak somewhere in the intake/charge-air path. You'll typically feel reduced power or sluggish acceleration, and the engine may go into a reduced-power mode. Typical repair costs on Buick range from $1,200 to $3,000, depending on the specific model and root cause.
Common Causes of P0299
- •Boost/intake leak (cracked or loose charge-air hose or intercooler)
- •Faulty or sticking turbo wastegate or actuator
- •Stuck or clogged variable-geometry turbo vanes (VGT)
- •Faulty boost pressure or MAP sensor
- •Leaking or disconnected vacuum/boost control lines
- •Restricted air intake or clogged air filter
- •Failed boost control solenoid
- •Worn or failing turbocharger
P0299 on Buick by Model
Buick Encore(1 issue)
- Turbocharger / Oil Supply Line Failure Causing Sudden Loss of Power2013-2018
The 1.4L turbo Encore is known for turbocharger failures, often tied to the turbo oil feed/supply line, that cause a sudden loss of power while driving and a persistent check engine light. NHTSA complaints document dangerous highway events where the vehicle abruptly lost acceleration. GM later issued a field action/warranty extension covering 2017-2018 Encore turbochargers for 10 years / 120,000 miles, with the repair replacing the turbo assembly and associated oil-feed seals and gaskets.
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View P0299 across all makes →Frequently Asked Questions
What does P0299 mean on Buick?▼
P0299 stands for "Turbo/Supercharger Underboost Condition." P0299 means the engine computer detected an underboost condition — the turbocharger or supercharger is producing less boost pressure than the PCM expects for the given conditions. The computer compares the manifold/boost pressure sensor reading to a target based on engine load, and when actual boost falls short, it sets this code. The most common real-world cause is a leak somewhere in the intake/charge-air path. You'll typically feel reduced power or sluggish acceleration, and the engine may go into a reduced-power mode. On Buick specifically, this code is documented across 1 model.
What causes P0299 on Buick vehicles?▼
Common causes on Buick: Boost/intake leak (cracked or loose charge-air hose or intercooler), Faulty or sticking turbo wastegate or actuator, Stuck or clogged variable-geometry turbo vanes (VGT), Faulty boost pressure or MAP sensor, Leaking or disconnected vacuum/boost control lines. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0299 on a Buick?▼
Repair costs on Buick range from $1,200 to $3,000, depending on the specific model and root cause.
Which Buick models have P0299 documented?▼
Au7o has documented P0299 on 1 Buick model: Encore.