P24E1NH3 Sensor Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- An NH3 sensor behind the SCR catalyst measures ammonia that slipped through unused, letting the controller trim dosing and detect overdosing or an aged catalyst. P24E1 is the general circuit code for this sensor: its signal is missing, implausible or erratic. Deutz lists P24E1 for its MD1 engine controller with SPN 4377 and FMI 2, i.e. unstable or wrong data. For the 2014 Ram 3500 to 5500 chassis cab with the 6.7 L Cummins, bulletin 18-042-20 offers two calibrations: one for trucks still equipped with the sensor, the other for trucks from which it has been taken off. CARB's heavy-duty rules require SCR sensors to be checked for circuit faults and rationality. Range, low, high and intermittent faults are P24E2 to P24E5; a lost CAN link to the sensor is U02A4.
- What you may notice
- Malfunction indicator lamp on
- Less precise DEF dosing, possible ammonia smell or higher NOx
- Likely causes
- LikelyNH3 sensor element or its electronics failed from heat and age
- PossibleHeat-damaged wiring or connector near the exhaust
- RareSoftware calibration issue, update available on some engines
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €150 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.