These instructions apply to the Mercedes C-Class Mk5 (W206) 2021-Present. For other models, please choose your vehicle here.
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When the wrench/spanner and an “A” or “B” service message appears on your Mercedes-Benz C-Class W206 (2021–present), the ASSYST PLUS maintenance counter has run down. You reset it from the instrument-cluster menu using the steering-wheel touch controls — no workshop tool needed. Do the service first.
Reset After the Service Only
ASSYST PLUS counts down by distance, time and driving conditions. Reset it only once the oil and filter (and anything else due) are done, or the next interval will be wrong.
How to Reset the W206 Service Indicator
- Close the bonnet, boot and all doors.
- Turn the ignition to position 1 and wake the cluster.
- On the left steering-wheel touchpad, open the menu and select the ‘CLASSIC’ display, then scroll to ‘Total distance’ (the odometer).
- Press and hold the OK button for ~5 seconds; within 1.5 seconds, press and hold OK again for ~3 seconds.
- The hidden menu appears (VEHICLE DATA / DYNAMOMETER TEST / ASSYST PLUS). Turn the ignition to position 2.
- Select ‘ASSYST PLUS’ → ‘FULL SERVICE’, then confirm the reset (‘Confirm’/‘Reset’).
If It Doesn’t Reset
- The timing is tight — the double OK-hold must be within 1.5 seconds; try again.
- A door/bonnet is open — the menu won’t arm; close everything and retry.
Frequently Asked Questions
How do I reset the service light on a Mercedes C-Class W206?
Via the cluster: CLASSIC menu → Total distance, double-hold OK to open the hidden menu, then ASSYST PLUS → FULL SERVICE → confirm.
Do I need a Star/diagnostic tool?
No — ASSYST PLUS resets from the dashboard. A tool is only needed for the separate oil-life/battery registration tasks.
What do A and B service mean?
Mercedes alternates a smaller ‘A’ and larger ‘B’ service. ASSYST PLUS picks the right one; reset after whichever you’ve done.
The message came back — why?
The reset wasn’t confirmed, or a separate fault is present. Repeat and confirm to the end.
If a warning light appeared with the service message, look it up on autodtcs.com. After battery work, see our W206 battery guide.
Disclaimer: The information on this page is provided for general guidance only. Always follow your official service manual and safety precautions when working on your vehicle. We are not responsible for errors, omissions, or any damage resulting from the use of this information.
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