OBD Guide

P0401

EGR A Flow Insufficient Detected

P0401 is an OBD-II diagnostic trouble code meaning: EGR A Flow Insufficient Detected. Common causes: egr valve clogged, egr solenoid malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Unstable engine idling
  • Reduced engine power
  • Increased fuel consumption
  • Detonation (knocking) in the engine

Causes

  • EGR valve clogged
  • EGR solenoid malfunction
  • Damage to vacuum lines
  • EGR valve position sensor malfunction
  • ECU software error

How to Fix

  1. Check the condition of the EGR valve and clean or replace if necessary
  2. Check the operation of the EGR solenoid
  3. Inspect vacuum lines for damage
  4. Check EGR valve position sensor
  5. Reset the error and check the system operation

Related codes

Error P0401 by Vehicle Brand

FAQ

What does the P0401 code mean?

P0401 is an OBD-II diagnostic trouble code that indicates: EGR A Flow Insufficient Detected

What causes a P0401 error code?

The most common causes of P0401 include: EGR valve clogged; EGR solenoid malfunction; Damage to vacuum lines; EGR valve position sensor malfunction.

How do I fix a P0401 diagnostic trouble code?

To fix P0401: Check the condition of the EGR valve and clean or replace if necessary. Check the operation of the EGR solenoid. Inspect vacuum lines for damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0401?

Limited driving only, diagnose soon

How much does it cost to fix P0401?

The estimated repair cost for P0401 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat