Mercedes-Benz S 500 2022 — technical service bulletin
Bulletin LI20.10-P-074284 · NHTSA communication 10207184 · issued Jan 26, 2022
Technical service bulletin
communication type
Equipment
component
2022
model years
3
vehicle entries
Official summary
Complaint Check engine light illuminated. Fault code P012800 current or stored in MRG1AMGV8 control unit. Cause Thermostat may not close completely Remedy 1-Perform coolant warmup test via fault P012800 and save the results 2-Drain coolant through fine sieve or filter and check for debris. 3-Remove and replace coolant thermostat. Check for any debris in thermostat or connections on engine. If debris found in step 2 or 3, flush engine and take pictures of debris. 4-Refill cooling circuit and clear faults. Warm engine during test drive. Allow to cool 6 hours. 5-Repeat coolant warmup test and sav
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.