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P0299

Turbocharger or Supercharger Underboost Condition

Your engine is not making the boost pressure it should. This usually causes weak acceleration, poor power, and sometimes a check engine light with limp mode.

Severity4/5 High
Can I drive?⚠ With caution

You can usually drive short distances gently, but power may be limited and the problem can get worse quickly. Avoid hard acceleration, towing, or highway merging until it is diagnosed.

DIY
$20–$350
Shop
$150–$2,500+
Difficulty
intermediate

What It Means

P0299 sets when the powertrain control module sees actual boost pressure lower than the commanded or expected boost level for a certain time and operating condition. The fault can be caused by boost leaks, control system problems, sensor errors, exhaust flow issues, or a worn turbocharger/supercharger.

Symptoms

Common Causes

1. Boost leak from a cracked intercooler hose, loose clamp, split charge pipe, or leaking intercoolerhigh
2. Faulty wastegate actuator, sticking wastegate, or boost control solenoid problemhigh
3. Vacuum line leak or damaged vacuum supply to turbo control componentshigh
4. Worn or failing turbocharger with shaft play, damaged compressor wheel, or poor boost outputmedium
5. Intake restriction such as a clogged air filter or collapsed intake ductmedium
6. Exhaust restriction or exhaust leak before the turbo reducing turbine energymedium
7. Faulty MAP sensor, boost pressure sensor, or MAF sensor causing incorrect boost readings or controlmedium
8. Diverter valve or bypass valve leaking boost pressuremedium
9. Low engine oil supply or oil contamination affecting turbo operationlow
10. PCM software issue or less common wiring/connectivity faultlow

Related Codes

FAQ

Can a boost leak cause P0299?

Yes. A leaking hose, cracked charge pipe, loose clamp, or leaking intercooler is one of the most common causes of P0299.

Will P0299 cause limp mode?

Yes. Many vehicles reduce power to protect the engine and turbo system when underboost is detected.

Can I keep driving with P0299?

Only cautiously and for short trips if the vehicle still runs normally enough to move safely. Continued driving can worsen turbo damage or leave you with very limited power.

Does P0299 always mean the turbo is bad?

No. Many P0299 cases are caused by leaks, bad vacuum lines, a faulty wastegate control system, or a sensor problem rather than a failed turbocharger.

What does underboost feel like?

The vehicle usually feels weak, slow to accelerate, and may struggle more than normal when climbing hills or merging onto the highway.