Common Symptoms
- Check engine light illuminated
- Reduced engine power or derate
- Increased DEF consumption
- Poor fuel economy
- Failed emissions test
Most Likely Root Causes
- Faulty NOx sensor
- Damaged or corroded wiring harness to NOx sensor
- Loose or corroded electrical connector at NOx sensor
- Intermittent ground connection
- ECM software issue
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Component Location
NOx sensor is typically mounted in the exhaust system downstream of the SCR catalyst on bank 1.
Manufacturer Notes
Diesel engines with selective catalytic reduction systems rely on accurate NOx sensor data for proper DEF dosing and emission control.
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