P20EF

SCR NOx Pre- Catalyst Efficiency Below Threshold Bank 1

Severity

🔴 High

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$56–278 (est.)

Symptoms

Check Engine Light Is On
Reduced engine power
Increased fuel consumption
Possible unpleasant smell of exhaust fumes
Low AdBlue message on the instrument panel

Causes

Low level or poor quality of AdBlue reagent
AdBlue injection nozzle malfunction
Contaminated or damaged catalytic converter
NOx sensor malfunction
Problems with SCR system wiring or connectors

How to Fix

Check the level and quality of AdBlue reagent
Diagnose the AdBlue injection system
Check the condition of the catalytic converter
Test NOx sensors and their wiring
If necessary, replace faulty SCR system components

Related codes

P20EE P20F0 P229F