In the spirit of the previous answer, and in the spirit of all moderators who simply point to "Search Functions", and in the spirit of my mother who when asked "where is my coat?", would reply, it's hanging up where it belongs...lol
Seriously when in doubt, just google everything, if it's a Mercedes question it pops up answers within the forum your asking the questions. So the answers I'm copy and pasting below took less time to find than it is to type this part of my reply.. ? ??
Answers from google below;
Mercedes-Benz scheduled services at affordable prices. Located in Westminster, CA. Call (714) 901-0099
www.powerhousegermanauto.com
lucasautocare.com
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The F actually signals the importance of the maintenance required and it's a critical one: change all filters and fluids (engine, brake, steering, transmission) , even the rear axle and especially the automatic transmission filter and fluid (don't believe the 100,000 mile service) or you better start saving $5,000 for a rebuilt tranny. Change all belts and save the old belts as a backup. Be sure to change the Cabin Charcoal (Carbon) air filter and the spark plugs too. Also all the suspension parts will be inspected thoroughly. Service F is a 6 hour service
To reset it turn on the ignition and get to the service warning. Hold the reset button for a few seconds and 'service menu' will pop up. In there just select the oil and confirm the reset.
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Recommendations- Service F+(Mercedes benz e class)
Fully synthetic oil replacement:
Oil filter replacement.
Air and cabin filter replacement.
Brake and transmission fluid change.
All fluid level check and top-up if necessary.
Spark plugs and serpentine belt replacement.
System update on ECU.
Reset maintenance counter.