YANMAR-P0403 serious Yanmar ›

EGR Control Circuit Malfunction

The YANMAR-P0403 (Yanmar) diesel fault code means: EGR Control Circuit Malfunction. 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.

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Keep driving?
Limited driving only
DIY difficulty
intermediate
Estimated cost
$100-$600

What Are the Symptoms of YANMAR-P0403?

  • EGR fault, no regen

What Causes YANMAR-P0403? (Most Likely First)

  • EGR solenoid open circuit Likely
  • Damaged EGR harness from heat Possible

Can I Still Drive with YANMAR-P0403?

Limited driving only. YANMAR-P0403 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 P0403?

Yanmar P0403: EGR Control Circuit Malfunction.

Can I keep operating with Yanmar code P0403?

Limited operation only -- finish task then shut down.

How much does Yanmar P0403 cost to fix?

Typical cost: $100-$600. Yanmar SmartAssist / YDT diagnostic software is often required.

Mechanics Guide Step-by-step diagnosis

How Do You Diagnose YANMAR-P0403?

  1. Ohm-test EGR solenoid.

  2. Check harness routing near turbo/exhaust.

Sources 1

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

  • SAE J2012Diagnostic Trouble Code Definitions (defines P0403 as a generic OBD-II code)

P0403 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 P0403 Hino moderate Exhaust Gas Recirculation Control Circuit Isuzu moderate Exhaust Gas Recirculation Control Circuit Kubota serious EGR Control Circuit

Which Vehicles Commonly Get YANMAR-P0403?

  • 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

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

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