These instructions apply to the Mercedes CLA Mk2 (C118) 2019-Present. For other models, please choose your vehicle here.
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When the wrench symbol and an “A” or “B” service message appears on your Mercedes-Benz CLA (C118, 2019–present), the ASSYST PLUS maintenance counter is due. You reset it from the instrument-cluster menu with the steering-wheel buttons — 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 once the oil and filter (and anything else due) are done.
How to Reset the CLA Service Indicator
- Close the bonnet, boot and all doors.
- Turn the ignition on (press start without the brake so it stays in ignition-on, not engine running).
- On the left steering-wheel touch controls, scroll to the ‘Trip’ menu.
- Hold the two control buttons together as prompted to reach the hidden ‘Workshop’ menu (VEHICLE DATA / DYNAMOMETER / ASSYST PLUS).
- Select ‘ASSYST PLUS’ → ‘Full service’ and confirm the reset.
If It Doesn’t Reset
- A door/bonnet is open — the menu won’t arm; close everything and retry.
- You didn’t confirm — step through ASSYST PLUS → Full service → confirm.
Frequently Asked Questions
How do I reset the service light on a Mercedes CLA?
Via the cluster: open the Trip menu, hold the two buttons together to reach the Workshop menu, then ASSYST PLUS → Full service → confirm.
Do I need a Star/diagnostic tool?
No — ASSYST PLUS resets from the dashboard.
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. 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 CLA 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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