What does code P21CE mean?

Q: What does code P21CE mean?

Reductant Quality Module Performance. P21CE indicates that the reductant quality module has detected a problem with the diesel exhaust fluid (DEF) quality or the module's ability to accurately assess it. The engine control module (ECM) sets this code when the reductant quality sensor signal or the module's internal performance does not meet expected parameters, often due to contaminated fluid, a faulty sensor, or wiring issues.

DTC codes / P21xx · Fuel and air metering / P21CE

P21CEReductant Quality Module Performance

P21CE indicates that the reductant quality module has detected a problem with the diesel exhaust fluid (DEF) quality or the module's ability to accurately assess it. The engine control module (ECM) sets this code when the reductant quality sensor signal or the module's internal performance does not meet expected parameters, often due to contaminated fluid, a faulty sensor, or wiring issues.

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.