P21B3

Closed Loop NOx Adsorber Control At Limit - Too High

Severity

🔴 High

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$56–167 (est.)

Symptoms

Increased fuel consumption
Reduced engine power
Check Engine Light Is On
Dips during acceleration
Unstable idling

Causes

NOx adsorber dirty or faulty
Problems with the EGR system
Low fuel quality
NOx sensor malfunction
Exhaust system leakage

How to Fix

Check the EGR system for clogging
Diagnose the condition of the NOx adsorber
Check the exhaust tract for leaks
Test NOx sensors
Replacing the NOx adsorber if necessary

Related codes

P21B2 P21B4 P20EE