top of page

P0400

Overview

Code

P0400

Code Type

P

Code Class

P0

System

Engine

Severity Level

Medium

Emissions Related

true

Drivability Impact

Minor

Diagnostic Protocol

OBD2

Freeze Frame Useful

true

Code Definition

Diagnostic trouble code P0400 indicates a general exhaust gas recirculation (EGR) flow malfunction

Symptoms

Rough idle; Reduced performance

Overview applies to this diagnostic code.

Affected Systems

On This Page

  • Code Definition

  • Symptoms

  • Affected Systems

  • Possible Causes

  • Diagnostic Steps

  • Drive Safety Notes​

More Resources

EGR emissions control system

Possible Causes

Stuck EGR valve; Clogged EGR passages

Diagnostic Steps

1 Command EGR valve operation; 2 Inspect EGR passages for blockage

Drive Safety Notes

Engine performance may be reduced

bottom of page