P21C5
Reductant Level Sensor A Stuck
P21C5 is an OBD-II diagnostic trouble code meaning: Reductant Level Sensor A Stuck. Common causes: crystallization of adblue in the sensor, mechanical jamming of the float. Estimated repair cost: $28–89.
Symptoms
- Check Engine Light
- Low AdBlue level message (even with a full tank)
- Reduced engine power
- Increased fuel consumption
- Problems starting the engine (in some models)
Causes
- Crystallization of AdBlue in the sensor
- Mechanical jamming of the float
- Sensor contamination
- Malfunction of the level sensor itself
- Problems with wiring or connectors
How to Fix
- Check AdBlue level and quality
- Clean the level sensor from crystallized deposits
- Check the electrical connections of the sensor
- Replace the reagent level sensor if necessary
- Reset the error and take a test drive
Related codes
Error P21C5 by Vehicle Brand
FAQ
What does the P21C5 code mean?
P21C5 is an OBD-II diagnostic trouble code that indicates: Reductant Level Sensor A Stuck
What causes a P21C5 error code?
The most common causes of P21C5 include: Crystallization of AdBlue in the sensor; Mechanical jamming of the float; Sensor contamination; Malfunction of the level sensor itself.
How do I fix a P21C5 diagnostic trouble code?
To fix P21C5: Check AdBlue level and quality. Clean the level sensor from crystallized deposits. Check the electrical connections of the sensor. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P21C5?
Yes, but get it checked soon
How much does it cost to fix P21C5?
The estimated repair cost for P21C5 is $28–89. Actual cost depends on your vehicle, location, and labor rates.
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