P21B2

Excessive Time To Enter Closed Loop NOx Adsorber Control

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$56–278 (est.)

Symptoms

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

Causes

NOx sensor malfunction
Leaks in the exhaust gas recirculation system
NOx converter is dirty or damaged
Problems with system solenoid valves
ECU software errors

How to Fix

Check the condition of NOx sensors and their connections
Diagnose the exhaust gas recirculation system for leaks
Assess the condition of the NOx converter
Check the operation of the system control valves
Update ECU software if necessary

Related codes

P21B1 P21B3 P21B4