Notes on avoiding damage to ignition system - AH15.10-P-0002-01AK

WARNING: This page does not describe the selected car, but rather 199 other vehicles, including the 2020 Mercedes-Benz SLC300, 2020 Mercedes-Benz SL550, 2020 Mercedes-Benz SL450, 2020 Mercedes-Benz S65 AMG, and 2020 Mercedes-Benz GLA250. However, it is still accessible from the selected car via links, so may be relevant.

ENGINE 266.920/940/960/980 in MODEL 169.0/3, 245.2

Before detaching the engine wiring harness connector or the vehicle wiring harness connector on the ME-SFI [ME] control unit remove the transmitter key from the EZS control unit.
Do not operate the ignition system when the electrical lines are not correctly connected.
Do not disconnect the electrical connectors at the ignition coils at starting speed or when the engine is running.
Only install original ignition system components.

Additionally for model 169, 245:

Do not remove ignition cable from the ignition coil or the spark plugs at starting speed or when the engine is running.
Check ignition cable and its sheath, replace if necessary.