Common Symptoms
- Check Engine Light illuminated
- Reduced engine power or derate mode
- Poor fuel economy
- Increased diesel exhaust fluid consumption
- Failed emissions test
- NOx sensor heater fault message on instrument cluster
Most Likely Root Causes
- Failed NOx sensor heater element
- Damaged or corroded NOx sensor wiring harness
- Short to voltage in NOx sensor heater circuit
- Failed engine control module
- Corroded NOx sensor connector
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Component Location
NOx sensor is installed in the exhaust system downstream of the diesel particulate filter or SCR catalyst, typically on the passenger side of the vehicle.
Manufacturer Notes
Diesel engines with selective catalytic reduction systems require proper NOx sensor heater operation for accurate emission control and regeneration strategy.
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