Freightliner Sprinter 1500 2019–2021 — technical service bulletin
Bulletin LI49.20-N-076565 · NHTSA communication 11021170 · issued Jul 23, 2025
Technical service bulletin
communication type
Unknown OR Other
component
2019–2021
model years
12
vehicle entries
Official summary
Check engine light with fault code P300E3B in the CDI control unit CDI (N3/28) Complaint Check engine light is illuminated with fault code P300E3B “The efficiency of component 'SCR catalytic converter' is not sufficient" stored in the CDI control unit (N3/28). Cause Excessive ammonia slip is being detected in the SCR system, often triggered by IUMPR (In-Use Monitor Performance Ratio) thresholds. This typically indicates that the SCR catalyst is not converting DEF (AdBlue) efficiently under moni- tored conditions. Common Driving Scenario: •Non-dynamic driving (e.g., highway cruising with cruise
Vehicles covered
- 2021 Freightliner Sprinter 1500
- 2021 Freightliner Sprinter 2500
- 2021 Freightliner Sprinter 3500
- 2021 Freightliner Sprinter 4500
- 2019 Freightliner Sprinter (VS30)
- 2020 Freightliner Sprinter (VS30)
- 2021 Mercedes-Benz Sprinter 1500
- 2021 Mercedes-Benz Sprinter 2500
- 2021 Mercedes-Benz Sprinter 3500
- 2021 Mercedes-Benz Sprinter 4500
- 2019 Mercedes-Benz Sprinter (VS30)
- 2020 Mercedes-Benz Sprinter (VS30)
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.