P24EE
NH3 Sensor Processor Performance
The microcontroller inside the smart NH3 slip sensor reports an internal performance fault — failed self-test, watchdog reset, or out-of-range plausibility checks. The sensor cannot guarantee its output value, the ECM marks the channel invalid and disables SCR closed-loop control on this branch.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Internal processor or firmware faultCommon
- Brown-out from supply voltage dipsPossible
- Module software outdated, reflash may resolveLess likely
Parts involved
- Nh3 Sensor
- Sensor Microcontroller
P24EE is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.