P0299Turbocharger/Supercharger "A" Underboost Condition
Boost pressure under load is below the commanded value. Very common on turbodiesel and direct-injection turbo gasoline engines as the turbo system ages — typically a leaking boost pipe, a sticky variable-geometry vane assembly, or a wastegate that no longer holds.
Can I keep driving? NO
STOP the vehicle in a safe place. Continuing to drive may cause serious engine damage or put your safety at risk.
Sistema Afectado
Aire / Combustible · Inyección, MAF, MAP, O₂
Relacionado con la mezcla aire-combustible: sensores de flujo, presión, inyectores o bomba.
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Symptoms You Will Notice
What you may observe when this code appears
- Check engine light on Significant power loss / limp mode Possible blue or black smoke from exhaust Whistling or hissing sound from intake
Possible Causes
The components or conditions that trigger this code
- 1Leak in intercooler pipe or hose VGT vanes stuck (diesel
- 2soot buildup) Wastegate stuck open or weak spring Turbo bearing worn (preceded by oil consumption / smoke)
How to Fix It — Step by Step
Recommended diagnostic and repair procedure
- 1Difficulty: hard. Estimated time: 0.5-10 hours. Estimated cost: €80-€
- 2Professional repair recommended
Note: This information is for general reference. For precise diagnostics and safety repairs, always consult a certified mechanic.
Estimated Cost
Approximate range in USD (varies by region and shop)
Sensors + injectors
* Diagnosis only: $50–$150
Quick Info
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