Mercedes-Benz AMG CLS53 2016–2027 — technical service bulletin

Bulletin LI20.10-P-075374 · NHTSA communication 11038176 · issued Sep 17, 2026

Technical service bulletin

communication type

Engine

component

2016–2027

model years

vehicle entries

Official summary

Complaint Red coolant warning in instrument cluster. Fault codes U019F00 or U019F87 current/stored in MRG1 control unit. Cause Various causes Remedy Perform guided test for fault code U019F with XENTRY diagnosis. Verify the following connections are clean and tight. Correct any problems and retest pump actuation: ‑12V plug at M75/11 ‑48V plug at M75/11 ‑48V connector X192/4 ‑Connections at 48V fuse box F153/2 ‑Sockets 1,2, and 5 at connector 2 of MRG1 control unit ‑M75/11 circuit 41 ground If actuation and above connections are OK, but resistance between M75/11 and engine block is less than 2

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.