NOx Sensor Heater Sense Circuit Range/Performance (Bank 1)
Common Symptoms
- Check Engine Light illuminated
- Reduced engine power or derate condition
- Poor fuel economy
- Failed emissions test
- Diesel exhaust fluid consumption warning
- SCR system efficiency codes may also be present
Most Likely Root Causes
- Faulty NOx sensor heater element
- Corroded or damaged NOx sensor wiring harness
- Exhaust leaks near NOx sensor
- Failed NOx sensor
- Water or contamination in sensor connector
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Component Location
The NOx sensor is mounted in the exhaust system upstream of the SCR catalyst on bank 1, typically near the turbocharger or downpipe.
Manufacturer Notes
Diesel engines with SCR systems require proper heater function for accurate NOx measurements during cold start and aftertreatment regeneration cycles.
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