What does code P24E8 mean?

Q: What does code P24E8 mean?

NH3 Sensor Heater Circuit High. P24E8 indicates that the powertrain control module has detected an abnormally high voltage on the heater circuit for the ammonia (NH3) sensor, which is used to monitor selective catalytic reduction efficiency on diesel vehicles. The heater is designed to bring the sensor to operating temperature quickly, and a high-voltage condition means the circuit is drawing too little current or is open, so the computer sets this code to flag a heater circuit fault.

DTC codes / P24xx · Auxiliary emission controls / P24E8

P24E8NH3 Sensor Heater Circuit High

P24E8 indicates that the powertrain control module has detected an abnormally high voltage on the heater circuit for the ammonia (NH3) sensor, which is used to monitor selective catalytic reduction efficiency on diesel vehicles. The heater is designed to bring the sensor to operating temperature quickly, and a high-voltage condition means the circuit is drawing too little current or is open, so the computer sets this code to flag a heater circuit 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.