Common Symptoms
- Check Engine Light illuminated
- NOx sensor heater malfunction indicator
- Reduced engine power or derate in diesel applications
- Failed emissions test
- SCR system efficiency warnings
Most Likely Root Causes
- Faulty NOx sensor heater element
- Open circuit in NOx sensor heater wiring harness
- Corroded or damaged NOx sensor connector
- Failed NOx sensor heater relay or control module
- Blown fuse in NOx sensor heater circuit
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Component Location
NOx sensor is typically located in the exhaust system downstream of the diesel particulate filter or SCR catalyst on bank 1.
Manufacturer Notes
Some diesel engines may enter reduced power mode if NOx sensor heater circuits remain open to protect aftertreatment system components.
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