These instructions apply to the Mercedes C-Class Mk3 (W204) 2007-2014.
For other models, please choose your vehicle here.
Short answer: you can reset the ASSYST PLUS service reminder on the Mercedes C-Class W204 (2007–2014) from the driver’s seat with the steering-wheel buttons — no tool. With the ignition on and the odometer showing, open the instrument-cluster menu, select ASSYST PLUS → Full Service → Confirm, choose Yes and confirm.
What the Service Message Means
The W204 uses ASSYST PLUS, which tracks the flexible service interval by mileage, time and driving conditions. A spanner symbol and a message such as “Service A/B in … days” appear as the interval approaches, and once it is due the message shows at each start. Carrying out the service does not clear it — the counter has to be reset.
Open the Instrument-Cluster Menu
Get in, close the doors, and turn the ignition on so the cluster is lit (engine off), with the total odometer (not a trip) shown in the display. Then, depending on your steering wheel:
- Wheel with an OK button: press and hold the phone/call button, then also press and hold OK (both together) until the driver-information menu opens — a few seconds. Timing varies by wheel generation, so hold until you actually see the menu.
- Older four-button wheel (no OK): press and hold the top-left and bottom-left buttons together until the battery voltage appears, release, then use the right-hand button to enter the menu and browse to ASSYST PLUS.
Reset the Service Reminder
- Scroll to ASSYST PLUS and press OK.
- Select Full Service and press OK.
- Select Confirm Full Service (or “Confirm service”) and press OK.
- Choose Yes, press OK, then Confirm and press OK.
Turn the ignition off. The service reminder is reset and should not reappear at the next start. To reset just a partial item (for example an oil service), pick that entry instead of Full Service.
Note: the exact prompt wording varies by cluster software — you may see “Confirm service”, “Confirm full service” or a single “Confirm”, and some cars ask you to confirm the oil grade used first (choose the listed/standard spec). Just follow the on-screen prompts to the final Yes/Confirm.
Before You Start
- Do the actual service first. Resetting the counter without doing the work just hides the real interval.
- Make sure the odometer is displayed before you open the menu — the button combination only works from the standard view.
Frequently Asked Questions
How do I reset the service light on a Mercedes W204?
With the ignition on and the odometer showing, open the cluster menu (phone + OK held together, or the two left buttons on a four-button wheel), then ASSYST PLUS → Full Service → Confirm → Yes → Confirm. No tool is needed.
Do I need a STAR diagnosis machine to reset the W204 service?
No. The dealer’s STAR system can extend the interval, but the standard service reset is done from the steering-wheel buttons as above.
My steering wheel has no OK button — how do I get into the menu?
Hold the two left-hand buttons together for about five seconds until the voltage shows, release, then use the right-hand button to open the menu and reach ASSYST PLUS.
The service message came straight back — why?
Either you exited before the final Confirm, you weren’t on the odometer view when you opened the menu, or a stored fault is holding the message on. Start again from the odometer and complete every confirmation step; if it still persists, have the system checked for fault codes.
What’s the difference between Full Service and the individual items?
Full Service resets the whole interval; the individual entries (such as oil) reset only that item. Choose the one that matches the work you carried out.
If a warning light or fault code appeared alongside the service message, look it up on our sister site autodtcs.com to see whether it relates to a fault or just the service interval.
Independent guide — not affiliated with Mercedes. Always follow your official service manual and safety precautions. Read our full disclaimer.