Powertrain
generic / SAE
P24EA
NH3 Sensor Supply Voltage Circuit
The supply rail that powers the NH3 slip sensor electronics (typically 5 V or 12 V from the dosing/SCR module) is out of tolerance. Without a stable supply the sensor cannot deliver a valid ammonia reading, and the ECM disables the closed-loop SCR strategy.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number4 / EA
Possible causes
- Open or shorted supply wire high
- Failing supply rail inside the dosing module medium
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 120–700 €
- Estimated time: 0.5–2 h
- Component: nh3 sensor
- Component: supply wiring
- Component: dosing module
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012