P24E3NH3 Sensor Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P24E3 means the NH3 sensor signal lies below the lowest value an intact sensor can deliver. Usual culprits are a short to ground between probe and its electronics module, a terminal pushed back in the connector or a defect inside the probe. On International trucks with the 2013 N13 engine, a matching condition is reported as SPN 5848 with failure mode 4, i.e. the signal voltage of the mid-bed ammonia sensor too low or grounded. No manufacturer publishes P24E3 itself. CARB requires out-of-range checks for emission sensors on heavy-duty engines. While the fault is present the controller cannot trust ammonia feedback and has to dose from its model. P24E4 is the high counterpart, P24E2 the plausibility fault.
- What you may notice
- Malfunction indicator lamp on
- Scan tool shows ammonia reading stuck at minimum
- Likely causes
- LikelyChafed harness between probe and sensor module shorting to ground
- PossibleInternal fault in the ammonia probe
- RareCorroded or pushed-back terminal at the probe connector
- 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: €100 – €1,400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.