P0299 on Fiat
Turbo/Supercharger Underboost Condition
P0299 on Fiat vehicles indicates turbo/supercharger underboost condition. Au7o has documented this code across 2 Fiat models — most commonly on 124 Spider, 500L. 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 Fiat range from $100 to $1,200, 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 Fiat by Model
Fiat 124 Spider(1 issue)
- Turbo Boost Leak from Intercooler Piping2017-2020
The charge piping between the turbocharger and intercooler develops leaks at the silicone coupler connections, causing loss of boost pressure and reduced power. The issue is more common on the Abarth tune.
Fiat 500L(1 issue)
- Turbo Wastegate Rattle2014-2020
The turbocharger wastegate develops a rattle or fluttering noise at idle and low RPM due to wear in the wastegate actuator linkage. The noise is more pronounced when the engine is cold.
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View P0299 across all makes →Frequently Asked Questions
What does P0299 mean on Fiat?▼
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 Fiat specifically, this code is documented across 2 models.
What causes P0299 on Fiat vehicles?▼
Common causes on Fiat: 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 Fiat?▼
Repair costs on Fiat range from $100 to $1,200, depending on the specific model and root cause.
Which Fiat models have P0299 documented?▼
Au7o has documented P0299 on 2 Fiat models: 124 Spider, 500L.