What does P0299 underboost mean?

P0299 means the turbocharger is not generating enough boost pressure to meet the ECU's target. The engine will feel noticeably less powerful. This can be caused by boost leaks, a wastegate fault, turbo wear, or airflow restrictions.

Can I drive with P0299?

Yes, but with significantly reduced power. The engine is not in immediate danger from underboost itself. However, the underlying cause (such as turbo bearing wear) can worsen. Drive to a workshop but avoid heavy loads or towing.

What is the most common cause of P0299?

Boost leaks are the most common cause. A loose hose clamp, cracked intercooler pipe, or split silicone coupler can allow pressurised air to escape before reaching the engine. These are often the cheapest and easiest fix.

How do I check for boost leaks?

The most reliable method is a boost leak test. Block the throttle body inlet, connect compressed air at low pressure (0.5-1 bar), and listen or use soapy water to find leaks. Common leak points are intercooler pipe connections, charge pipe joints, and the intercooler itself.

How much does it cost to fix P0299?

Fixing a boost leak costs 40-200 EUR. A boost solenoid replacement runs 50-170 EUR. Wastegate repair is 140-500 EUR. If the turbo itself is worn out, replacement costs 700-2,300 EUR including parts and labour.

P0299: Turbocharger/Supercharger "A" Underboost Condition

Quick Answer

Safe to drive (short-term)

P0299 means the turbocharger is not producing enough boost pressure to meet the ECU's target value during normal driving. The engine will feel noticeably less powerful, especially under acceleration. Common causes include boost leaks in the charge piping, a stuck-open wastegate, or a worn turbocharger with failing bearings.

Severity: Moderate · Fuel System
Estimated repair cost: From €20 to €2300+, varies by vehicle

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What does P0299 mean?

P0299 is a fuel system-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P0299 and illuminates the check engine light.

Where it is on the car

Air filter
Turbocharger
Wastegate or boost control actuator
Intercooler
Boost pressure sensor
Throttle, intake manifold and engine

This code says boost is too low, not that the turbo has failed. The usual causes are a leaking pipe, clamp or intercooler, then a sticking wastegate or vane actuator. Check those before the turbo.

What are the symptoms of P0299?

If your vehicle has triggered P0299, you may notice one or more of these symptoms:

Check engine light on
Significant loss of power and acceleration
Limp mode (reduced engine power warning)
Turbo whistle absent or reduced
Black smoke from exhaust under acceleration
Higher than normal exhaust gas temperatures

What causes P0299?

Here are the most common causes of P0299:

Boost leak (intercooler pipes, hose clamps, cracked intercooler)
: high
Wastegate stuck open or not closing fully
: high
Worn turbocharger (shaft play, damaged compressor wheel)
: medium
Clogged air filter restricting airflow to turbo
: medium
Faulty boost control solenoid
: medium
Blocked catalytic converter or DPF creating exhaust backpressure
: low

Is it safe to drive with P0299?

Generally yes, for short-term driving. You can drive to a workshop but expect significantly reduced power. The engine is not in immediate danger but the underlying cause should be repaired soon to prevent further turbo damage.

How do you diagnose P0299?

Follow these steps to pinpoint the root cause of P0299:

Use a scan tool to monitor actual boost pressure versus target boost. If actual pressure is consistently 0.3+ bar below target under load, the underboost is confirmed
Check the air filter first. A severely clogged filter restricts airflow and limits boost. Replace if dirty
Perform a boost leak test by pressurising the intake system with compressed air (0.5-1 bar) and listening/feeling for leaks at intercooler pipes, hose connections, and the intercooler itself
Inspect the wastegate by checking if the actuator rod moves freely. Disconnect the vacuum/pressure line and verify the wastegate closes fully. A stuck-open wastegate allows exhaust to bypass the turbo
Check the turbo for shaft play by removing the intake pipe and wiggling the compressor wheel. More than 1 mm of radial play indicates worn bearings
If no boost leaks or turbo wear found, check for exhaust restrictions (blocked DPF or catalytic converter) using a backpressure test

How much does P0299 cost to fix?

Repair costs for P0299 vary depending on the root cause and your vehicle. Here are typical estimates:

Repair	Parts Cost	Labor Cost	Total Estimate	DIY Difficulty
Fix boost leak (tighten clamps, replace hose)	€10–€80	€30–€120	€40–€200	Moderate
Replace air filter	€10–€30	€10–€20	€20–€50	Easy
Replace boost control solenoid	€20–€80	€30–€90	€50–€170	Easy
Replace or repair wastegate actuator	€60–€250	€80–€250	€140–€500	Professional
Replace turbocharger	€400–€1500	€300–€800	€700–€2300	Professional

Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.

Engines known for this code

P0299 on specific vehicles

P0299 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

P0299 on Volkswagen

Volkswagen Golf

See Volkswagen-specific causes & cost

P0299 on Ford

Ford Focus

See Ford-specific causes & cost

Skoda

Skoda Octavia

2008-2024

Shares the VW 1.4 TSI and 2.0 TDI engines. The same boost leak and turbo actuator issues apply. Skoda uses slightly different charge pipe routing which can have different failure points. The 1.8 TSI in the Octavia RS is also susceptible to wastegate issues.

Peugeot

Peugeot 308

2007-2024

The 1.6 THP (EP6DT) turbo engine is known for oil feed line coking that leads to turbo failure. P0299 can be an early warning sign. The 1.6 BlueHDi diesel can also develop P0299 from DPF back-pressure issues or turbo actuator faults.

These codes are often seen alongside P0299 or indicate related issues:

Common questions about P0299

What does P0299 underboost mean?: P0299 means the turbocharger is not generating enough boost pressure to meet the ECU's target. The engine will feel noticeably less powerful. This can be caused by boost leaks, a wastegate fault, turbo wear, or airflow restrictions.
Can I drive with P0299?: Yes, but with significantly reduced power. The engine is not in immediate danger from underboost itself. However, the underlying cause (such as turbo bearing wear) can worsen. Drive to a workshop but avoid heavy loads or towing.
What is the most common cause of P0299?: Boost leaks are the most common cause. A loose hose clamp, cracked intercooler pipe, or split silicone coupler can allow pressurised air to escape before reaching the engine. These are often the cheapest and easiest fix.
How do I check for boost leaks?: The most reliable method is a boost leak test. Block the throttle body inlet, connect compressed air at low pressure (0.5-1 bar), and listen or use soapy water to find leaks. Common leak points are intercooler pipe connections, charge pipe joints, and the intercooler itself.
How much does it cost to fix P0299?: Fixing a boost leak costs 40-200 EUR. A boost solenoid replacement runs 50-170 EUR. Wastegate repair is 140-500 EUR. If the turbo itself is worn out, replacement costs 700-2,300 EUR including parts and labour.

Read our detailed guides

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