YANMAR-P0299 serious Yanmar ›

Turbocharger Underboost

The YANMAR-P0299 (Yanmar) diesel fault code means: Turbocharger Underboost. This is a serious severity code.

Unverified. We could not confirm this code's definition against freely available manufacturer documentation, so treat the meaning, severity and fix guidance on this page as unconfirmed. Check it against the manufacturer's service information for your exact model and serial range before acting on it. This page is kept out of search engines for that reason, and we are working through this family manual by manual.

My Garage →
Keep driving?
Limited driving only
DIY difficulty
intermediate
Estimated cost
$50-$2,500

What Are the Symptoms of YANMAR-P0299?

  • Severe power loss
  • Black smoke under load

What Causes YANMAR-P0299? (Most Likely First)

  • Split charge-air boot Very Likely
  • VGT vanes stuck with soot Likely
  • Plugged DPF back-pressure Possible

Can I Still Drive with YANMAR-P0299?

Limited driving only. YANMAR-P0299 is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.

Frequently Asked Questions

What is Yanmar code P0299?

Yanmar P0299: Turbocharger Underboost. This code is reported on Yanmar equipment running the described engine family.

Can I keep working with Yanmar code P0299?

Limited operation only -- finish the current task then shut down for repair.

How much does Yanmar P0299 cost to fix?

Estimated repair cost: $50-$2,500. Off-road diesel shop labor runs $125-$175/hr in 2026. Dealer diagnostic software (Yanmar SmartAssist / YDT) is usually required.

Mechanics Guide Step-by-step diagnosis

How Do You Diagnose YANMAR-P0299?

  1. Smoke-test intake under pressure.

  2. Scan VGT position vs. command.

  3. Check DPF differential pressure.

Sources 1

This page is built from documented references. Verify against your own service info before repair work.

  • SAE J2012Diagnostic Trouble Code Definitions (defines P0299 as a generic OBD-II code)

P0299 on Other Platforms

The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown:

Gas / Automotive (OBD-II) Generic OBD-II definition for P0299 Bobcat serious Turbocharger Underboost Duramax serious Turbo/Super Charger Underboost Hino serious Turbo/Super Charger Underboost Isuzu serious Turbo/Super Charger Underboost Kubota serious Turbocharger Underboost PACCAR serious Turbo/Super Charger Underboost Perkins serious Turbocharger Underboost

Which Vehicles Commonly Get YANMAR-P0299?

  • Yanmar SA221 / SA324 / SA424 compact tractors
  • Yanmar YT235 / YT347 / YT359 compact tractors
  • Yanmar LX4100 / LX4900 utility tractors
  • Yanmar ViO17 / ViO25 / ViO35 / ViO45 / ViO55 / ViO80 mini excavators
  • Yanmar B27-3 / B37-3 / B50-3 compact excavators
  • Cub Cadet Yanmar Ex3200 / Lx410 compact tractors (rebadged)
  • John Deere 17G / 26G / 35G compact excavators (Yanmar powered)
  • Takeuchi TB210R / TB216 / TB230 mini excavators (Yanmar powered)

Explore More

More Yanmar codes → Diesel home All diesel codes Heavy-duty Guides

Was this helpful?

Send this to whoever is fixing the truck — your tech, or the person asking what the fault means.