P203B

Reductant Level Sensor A Circuit Range/Performance

Severity

⚠️ Medium

Can you drive?

Yes, but get it checked soon

Approx. repair cost

$56–167 (est.)

Symptoms

Check Engine light comes on
Low AdBlue level message (even with a full tank)
Reduced engine power
Engine speed limit
Possible problems with starting after several cycles

Causes

AdBlue level sensor malfunction
Open or short circuit in the sensor circuit
Poor contact in the sensor connector
Problems with the SCR control unit
Sensor contamination with crystallized AdBlue

How to Fix

Check the level and quality of AdBlue fluid
Inspect the connector and wiring of the level sensor
Check sensor resistance (compare with factory values)
Clean the sensor from crystallized deposits
If necessary, replace the AdBlue level sensor

Related codes

P203A P203C P204F