P24E1
NH3 Sensor Circuit
A general circuit fault on the NH3 (ammonia) sensor - measures ammonia slip downstream of the SCR catalyst to detect AdBlue overdose.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Open in sensor or wiringCommon
Parts involved
- Nh3 Sensor
P24E1 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.