What does code P24E4 mean?

Q: What does code P24E4 mean?

NH3 Sensor Circuit High. P24E4 indicates that the powertrain control module has detected an abnormally high voltage on the ammonia (NH3) sensor circuit, which is used to monitor the selective catalytic reduction system on diesel vehicles. The sensor's signal wire is reading above the expected range, often due to a short to voltage or an open circuit, and the module sets this code to alert the driver that emissions control may be compromised.

DTC codes / P24xx · Auxiliary emission controls / P24E4

P24E4NH3 Sensor Circuit High

P24E4 indicates that the powertrain control module has detected an abnormally high voltage on the ammonia (NH3) sensor circuit, which is used to monitor the selective catalytic reduction system on diesel vehicles. The sensor's signal wire is reading above the expected range, often due to a short to voltage or an open circuit, and the module sets this code to alert the driver that emissions control may be compromised.

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.