HINO-P0401 moderate Hino ›

Exhaust Gas Recirculation Flow Insufficient Detected

The HINO-P0401 (Hino) diesel fault code means: Exhaust Gas Recirculation Flow Insufficient Detected. This is a moderate severity code.

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Keep driving?
Short distances only
DIY difficulty
intermediate
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What Are the Symptoms of HINO-P0401?

  • Check Engine light
  • Possible reduced power or higher exhaust temperatures

What Causes HINO-P0401? (Most Likely First)

  • EGR valve sticking closed from soot build-up High
  • Restricted or plugged EGR cooler High
  • EGR flow, position or differential-pressure sensor reading wrong Medium

Can I Still Drive with HINO-P0401?

Short distances only. HINO-P0401 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.

Frequently Asked Questions

What does P0401 mean on a Hino?

P0401 means Exhaust Gas Recirculation Flow Insufficient Detected. The control module measured less EGR flow than it commanded.

Is P0401 a Hino-specific code?

No. P0401 is a generic OBD-II code defined by SAE J2012, so it means the same thing on any vehicle that sets it. The exact conditions Hino uses to set it on its diesels are in Hino service information.

Mechanics Guide Step-by-step diagnosis

How Do You Diagnose HINO-P0401?

  1. Command the EGR valve on a scan tool and compare commanded and actual position.

  2. Inspect the EGR valve and passages for soot build-up.

  3. Check the EGR cooler for restriction.

Sources 3

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

P0401 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 P0401 Bobcat moderate EGR Insufficient Flow Detected Duramax moderate Exhaust Gas Recirculation Flow Insufficient Detected Isuzu moderate Exhaust Gas Recirculation Flow Insufficient Detected Kubota moderate EGR Flow - Insufficient PACCAR moderate Exhaust Gas Recirculation Flow Insufficient Detected Power Stroke moderate Exhaust Gas Recirculation Flow Insufficient Detected Yanmar moderate EGR Insufficient Flow Detected

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