P21AA
Reductant Level Sensor B Circuit Low
P21AA is an OBD-II diagnostic trouble code meaning: Reductant Level Sensor B Circuit Low. Common causes: low level of reductant (adblue) in the tank, reductant level sensor fault b. Estimated repair cost: $33–89.
Symptoms
- Check Engine Light Is On
- Low AdBlue message on the instrument panel
- Possible engine power limitation
- Increased fuel consumption
- Increased NOx emissions
Causes
- Low level of reductant (AdBlue) in the tank
- Reductant level sensor fault B
- Open or short circuit in the sensor circuit
- Poor contact in the sensor connector
- SCR control module malfunction
How to Fix
- Check and, if necessary, add reductant (AdBlue)
- Check the integrity of the sensor wiring and connectors
- Test reductant level sensor B
- If necessary, replace the level sensor
- Check the operation of the SCR control module
Related codes
Error P21AA by Vehicle Brand
FAQ
What does the P21AA code mean?
P21AA is an OBD-II diagnostic trouble code that indicates: Reductant Level Sensor B Circuit Low
What causes a P21AA error code?
The most common causes of P21AA include: Low level of reductant (AdBlue) in the tank; Reductant level sensor fault B; Open or short circuit in the sensor circuit; Poor contact in the sensor connector.
How do I fix a P21AA diagnostic trouble code?
To fix P21AA: Check and, if necessary, add reductant (AdBlue). Check the integrity of the sensor wiring and connectors. Test reductant level sensor B. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P21AA?
Yes, but get it checked soon
How much does it cost to fix P21AA?
The estimated repair cost for P21AA is $33–89. Actual cost depends on your vehicle, location, and labor rates.
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