NH3 Sensor Supply Voltage Circuit High
The NH3 slip sensor supply voltage rises above the upper limit. Either the supply is shorted to battery voltage or an internal regulator in the dosing module has failed open. The sensor electronics may be damaged if the condition persists, so the ECM disables the input.
Affected components
- Nh3 sensor
- Supply wiring
- Dosing module
Common causes
- High likelihood: Supply line shorted to battery voltage
- Medium likelihood: Failed voltage regulator in the dosing module
- Low likelihood: Connector pins corroded - high contact resistance
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.