Code P0299 (Turbocharger Underboost) on the 6.7L Power Stroke means the turbo is not producing the boost the ECM expects. This guide covers what triggers P0299, how to diagnose it, and the parts that fix it.
What P0299 means
The 6.7L Power Stroke uses a variable-geometry turbo. P0299 sets when measured boost falls below the commanded target - most often a sticking VGT, a boost leak, or a failing actuator.
Common causes
- Sticking VGT vanes from soot buildup
- A failing turbo actuator
- Boost leaks in the charge-air plumbing/intercooler
- Restricted air intake or a clogged air filter
- Worn turbo bearings
Symptoms you'll notice
- Sluggish acceleration and lost power, worst when towing
- Limp mode in severe cases
- Excess smoke
- A whistle or hiss from a boost leak
How to diagnose it
Check for boost leaks in the plumbing first (a split boot or loose clamp is common and cheap). Then compare commanded vs actual VGT vane position and listen for bearing noise. A soot-bound VGT caught early may clean up; real wear means the turbo or cartridge.
The fix
Fix a boost leak by replacing the failed boot/clamp. A failed actuator is replaced or recalibrated; a soot-bound or worn VGT gets cleaned, a new cartridge, or a complete turbo. Match any turbo to your exact year and keep EGTs reasonable.
Frequently asked questions
What is the most common cause of P0299?
A sticking VGT or a boost leak in the intercooler plumbing. Check the boots and clamps before the turbo.
Can I drive with P0299?
Briefly, but it may enter limp mode. Diagnose promptly to avoid being stuck down on power.
Need the part?
We stock the parts these trucks need. Shop 6.7L Power Stroke Turbochargers →