These instructions apply to the Mercedes GLA Mk2 (H247) 2020-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 GLA (H247, 2020–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 GLA Service Indicator
- Close the bonnet, boot and all doors.
- Turn the ignition to position 2.
- On the steering-wheel touch controls, scroll to the ‘Trip’ menu.
- Press and hold the OK button; within 1 second, also press the phone/back button, and keep both held for about 5 seconds.
- The hidden ‘Workshop’ menu appears (VEHICLE DATA / DYNAMOMETER TEST / ASSYST PLUS).
- Select ‘ASSYST PLUS’ → ‘Full service’ and confirm the reset.
If It Doesn’t Reset
- The timing is tight — the second button must follow within 1 second; 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 GLA?
Via the cluster: open the Trip menu, hold OK then the second button together ~5 seconds 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 GLA 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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