NH3 Sensor Heater Circuit Performance
The heater of the NH3 slip sensor is electrically intact, but the warm-up profile or steady-state temperature feedback does not match the ECM model. The sensor takes too long to reach operating temperature or drifts away from setpoint, so SCR closed-loop control is delayed or held off.
Affected components
- Nh3 sensor heater
- Sensor element
Common causes
- High likelihood: Aged heater with increased resistance
- Medium likelihood: Poor thermal contact between heater and sensing cell
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.