P0299 on MINI
Turbo/Supercharger Underboost Condition
P0299 on MINI vehicles indicates turbo/supercharger underboost condition. Au7o has documented this code across 2 MINI models — most commonly on Cooper S, GP. 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 MINI range from $60 to $2,500, 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 MINI by Model
MINI Cooper S(1 issue)
- Turbocharger Oil Feed Line Leak and Turbo Failure2007-2013
The turbo oil feed and return lines on R56 Cooper S develop leaks at the banjo bolt connections. Oil starvation to the turbo bearing leads to premature turbo failure. The oil return line can also coke up from heat cycling, restricting flow.
MINI GP(2 issues)
- Turbocharger Oil Feed Line Leak and Carbon Buildup2013-2021
The GP's high-output turbocharged engine is pushed harder than standard Cooper S models, making it more susceptible to turbo oil feed line leaks and carbon buildup on intake valves. The banjo bolt oil feed line seal hardens over time, causing oil to drip onto the exhaust manifold. Direct injection also causes severe intake valve carbon deposits that reduce performance.
- Intercooler Boost Pipe Blowoff / Silicone Coupler Failure (N14/N18/B48)2013-2023
The factory intercooler-to-throttle body boost pipes on the GP2 and GP3 use silicone couplers secured by worm-drive clamps that are prone to cracking, splitting, or blowing off under sustained high-boost track use. The N18 and B48 engines in GP specification run elevated boost pressure compared to standard Cooper S variants, accelerating coupler fatigue. Owners report a sudden loss of power accompanied by a loud 'pop' or hiss from the engine bay as boost pressure escapes.
Looking for P0299 on a different make?
View P0299 across all makes →Frequently Asked Questions
What does P0299 mean on MINI?▼
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 MINI specifically, this code is documented across 2 models.
What causes P0299 on MINI vehicles?▼
Common causes on MINI: 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 MINI?▼
Repair costs on MINI range from $60 to $2,500, depending on the specific model and root cause.
Which MINI models have P0299 documented?▼
Au7o has documented P0299 on 2 MINI models: Cooper S, GP.