What does code P21C5 mean?

Q: What does code P21C5 mean?

Reductant Level Sensor A Stuck. P21C5 indicates that the powertrain control module has detected a stuck condition in the reductant level sensor circuit, meaning the sensor signal is not changing as expected when the diesel exhaust fluid level should be rising or falling. The computer compares the sensor voltage against known values during key-on and running conditions and flags the code when the signal remains fixed for too long.

DTC codes / P21xx · Fuel and air metering / P21C5

P21C5Reductant Level Sensor A Stuck

P21C5 indicates that the powertrain control module has detected a stuck condition in the reductant level sensor circuit, meaning the sensor signal is not changing as expected when the diesel exhaust fluid level should be rising or falling. The computer compares the sensor voltage against known values during key-on and running conditions and flags the code when the signal remains fixed for too long.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.