What does code P21AE mean?

Q: What does code P21AE mean?

Reductant Level Sensor C Circuit Range/Performance. P21AE indicates that the powertrain control module (PCM) has detected an out-of-range or erratic signal from the reductant level sensor 'C' circuit, which monitors the diesel exhaust fluid (DEF) level in the tank. The PCM compares the sensor voltage against expected values for the current conditions and sets this code when the signal falls outside the valid range or does not change as expected.

DTC codes / P21xx · Fuel and air metering / P21AE

P21AEReductant Level Sensor C Circuit Range/Performance

P21AE indicates that the powertrain control module (PCM) has detected an out-of-range or erratic signal from the reductant level sensor 'C' circuit, which monitors the diesel exhaust fluid (DEF) level in the tank. The PCM compares the sensor voltage against expected values for the current conditions and sets this code when the signal falls outside the valid range or does not change as expected.

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.