Mercedes-Benz C 300 2022–2023 — technical service bulletin
Bulletin LI07.70-P-078547 · NHTSA communication 11026829 · issued Dec 18, 2025
Technical service bulletin
communication type
Engine
component
2022–2023
model years
4
vehicle entries
Official summary
Complaint Engine idle fluctuates or stumbles at approximately 7 second interval. No relevant fault codes are stored. If fault codes are stored or check engine light illuminated, this should be diagnosed separately. Cause Torque signal mismatch between MRG and PTCU control units. Only effects version 20B of PTCU. Remedy Update software of powertrain control unit N127. New software version: MY 2022- A2549021611 MY 2023- A2549023610
Vehicles covered
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.