What are the most likely causes of P0299?

Charge-air leak between turbo and cooler; Variable geometry stuck with soot; Plugged air filter

How do you diagnose code P0299?

1) Pressurize the charge-air system — Holds pressure with no audible leak 2) Check air filter restriction — Within specification

What part is usually replaced for P0299 and how much does it cost?

Turbo (VGT) actuator: $600–$2,200 USD (aftermarket to dealer), plus 2–5 h of labor.

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P0299

Q: What does truck fault code P0299 mean?

The turbo is not making the boost the engine asks for. Turbocharger underboost condition. On diesel trucks it is almost always a charge-air leak or a stuck variable geometry, and it shows up with power loss and black smoke.

CAUTION

Turbo underboost

The turbo is not making the boost the engine asks for.

P0299: The turbo is not making the boost the engine asks for. Caution: you can keep driving carefully, but the engine may derate; get it addressed soon.

Mechanical · Air intake / Turbo

Can I keep driving?

Caution: you can keep driving carefully, but the engine may derate; get it addressed soon.

What it means

Turbocharger underboost condition. On diesel trucks it is almost always a charge-air leak or a stuck variable geometry, and it shows up with power loss and black smoke.

Most likely causes

Charge-air leak between turbo and cooler
Very likely
Variable geometry stuck with soot
Very likely
Plugged air filter
Likely
Exhaust leak ahead of the turbo
Likely

Tests, cheapest and most decisive first

1. Pressurize the charge-air system
Expected result: Holds pressure with no audible leak
Tool: Pressure test kit
2. Check air filter restriction
Expected result: Within specification
Tool: Restriction gauge