Possible Causes
- Purpose of the DTC
- Selective catalytic reduction - reduced catalyst Nox conversion efficiency by active monitoring
- The SCR device ammonia storage capability is greatly reduced or the device is missing
- Electrical Cause
- Mechanical Cause
- Control Module Cavity
- Monitor Description
- SCR - reduced catalyst Nox conversion efficiency detected by active monitoring but not detected by active monitoring; on two consecutive occasions
- The SCR device ammonia storage capability is greatly reduced or the device is missing
- Prioritized List of Possible Causes
- Defective SCR catalyst (aged)
- Deficient DEF reagent delivery
- Diesel exhaust fluid injector partial delivery
- Damaged exhaust metal work
- SCR catalyst damage