top of page

P0491

Overview

Code

P0491

Code Type

P

Code Class

P0

System

Emissions

Severity Level

Medium

Emissions Related

true

Drivability Impact

Major

Diagnostic Protocol

OBD2

Freeze Frame Useful

true

Code Definition

Diagnostic trouble code P0491 indicates insufficient EGR flow detected in the exhaust system

Symptoms

Poor acceleration; Engine stalling

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 flow control

Possible Causes

Clogged EGR valve; Failed EGR valve solenoid

Diagnostic Steps

1 Inspect EGR valve 2 Check for carbon buildup

Drive Safety Notes

Potential for engine damage if ignored

bottom of page