What does code P24EC mean?

Q: What does code P24EC mean?

NH3 Sensor Supply Voltage Circuit High. P24EC indicates that the powertrain control module (PCM) has detected a high voltage condition on the supply circuit for the ammonia (NH3) sensor, which is used in selective catalytic reduction (SCR) systems to monitor NOx reduction efficiency. The PCM expects the sensor's supply voltage to remain within a calibrated range, and a sustained high reading suggests an open circuit, short to voltage, or internal sensor fault.

DTC codes / P24xx · Auxiliary emission controls / P24EC

P24ECNH3 Sensor Supply Voltage Circuit High

P24EC indicates that the powertrain control module (PCM) has detected a high voltage condition on the supply circuit for the ammonia (NH3) sensor, which is used in selective catalytic reduction (SCR) systems to monitor NOx reduction efficiency. The PCM expects the sensor's supply voltage to remain within a calibrated range, and a sustained high reading suggests an open circuit, short to voltage, or internal sensor fault.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

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