Common Symptoms
- Check engine light or malfunction indicator lamp illuminated
- DEF system warning light or message on instrument cluster
- Reduced engine power or derate condition
- Increased diesel exhaust emissions or failed emissions test
- DEF consumption appears abnormal or inconsistent
Most Likely Root Causes
- Faulty reductant injector or internal nozzle clogging
- Damaged or corroded wiring harness to reductant injector
- Poor electrical connection at injector connector
- Failed reductant injector driver circuit in control module
- Contaminated or crystallized DEF in injector
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Component Location
The reductant injector is located in the exhaust system upstream of the SCR catalyst, typically mounted on the decomposition tube or exhaust pipe.
Manufacturer Notes
Diesel engines with SCR aftertreatment require proper DEF quality and regular maintenance to prevent injector fouling and circuit faults.
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