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P0401 EGR flow insufficient detected

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EGR flow insufficient detected, readable through chat.

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System
Emissions control
Component
EGR system

Symptoms

  • Check engine light on
  • Service electronic throttle control message
  • Diesel particulate filter regeneration disabled (diesel engines)

Common causes

  • Engine control software not up to date
  • Faulty mass air flow sensor
  • Dirty air filter or restricted intake or exhaust
  • Intake or EGR leak
  • EGR air flow control valve binding
  • Clogged or damaged EGR cooler or tubes
  • Faulty EGR valve

Guides for this code

Pencil sketch of a Ram 1500 in a garage
Diagnostics & Repair

P0401 on a 2014-2018 Ram 1500 EcoDiesel: Low EGR Flow, Causes, Fix

JC Landry · Oct 30, 2026

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