For a CLK200 Kompressor C209 coupé or A209 cabriolet, plan servicing around the exact engine, the ASSYST reminder and the dated maintenance history. The A or B message identifies a service type; it does not tell you that every filter, spark plug or fluid needs replacing at that visit.
Covered cars: CLK200 Kompressor C209 coupé and A209 cabriolet with the 1,796 cc petrol M271.940 or M271.955 engine. The older C208/A208, CLK200 CGI, V6, diesel and AMG versions need their own specifications. Registration year alone is not a reliable parts check.
Which CLK200 Kompressor do you have?
| MANN application | Engine and output | Catalogue dates |
|---|---|---|
| 209.342 / 209.442 | M271.940; 120 kW / 163 hp | September 2002–June 2006 |
| 209.341 / 209.441 | M271.955; 135 kW / 184 hp | July 2006–October 2009 |
These are MANN catalogue application dates, rather than a promise that a UK registration plate identifies the changeover. Check the model and engine details in the vehicle documentation. Both variants are 1.8-litre Kompressor petrol engines, but that shared description does not remove the need to check individual parts.
The 2004 Mercedes manual includes the 120 kW CLK200 Kompressor; the later 2008 manual includes the 135 kW version. They provide better starting points than an overseas manual whose engine table starts with larger CLK models.
What do Service A and Service B mean on this CLK?
The reviewed CLK manuals call the system ASSYST. They describe A and B service messages, with the later manual distinguishing a smaller A service from a larger B service. Record the full message and whether the countdown is in days or distance.
Ask the workshop to itemise the inspections and any additional operations due for the actual car. An air filter last renewed recently should have its own history; a service letter cannot reconstruct that date. Equally, an old invoice headed “Service B” does not prove every age-related job was completed.
For general context, our Service A and Service B guides explain why the displayed service and the final job list are different things.
A stored cabriolet still needs a calendar history
If the CLK is a weekend car, note the dates as carefully as the mileage. The 2008 manual says ASSYST does not account for periods when the battery is disconnected. Tell the workshop how long the car was stored with it disconnected so the remaining time can be interpreted correctly.
Do not regard a long countdown after storage as proof that all maintenance is current. Keep the last invoice, renewal dates and any periods off the road together. A battery issue, roof fault or warning lamp also deserves its own diagnosis rather than being folded into a routine service assumption.
Check these records before booking
| Item | What to look for |
|---|---|
| Engine oil and oil filter | Date, mileage, exact oil product, MB approval and filter reference. |
| Engine air filter | A separate renewal entry; it is not the cabin filter. |
| Cabin / pollen filtration | Part reference, steering side and THERMATIC or THERMOTRONIC system. |
| Spark plugs | Full plug reference, engine-number application and replacement date. |
| Brake fluid | Actual renewal, distinguished from checking the level. |
| Gearbox servicing | Transmission identity and evidence of any separate fluid/filter work. |
| Cabriolet roof or other symptoms | A description of the fault and any diagnostic report, separate from scheduled work. |
The 2004 manual specifies brake-fluid renewal every two years. Confirm the applicable maintenance requirements for the car and its manual, including later editions. For filters, plugs and gearbox work, use the vehicle’s service documentation to establish the time and mileage requirements; the parts lists in our buying guide establish applications, not intervals.
Make a comparable garage quotation
- Supply the full reminder, mileage, engine details and maintenance history.
- Ask for the included inspections, labour and VAT to be clear.
- Separate work that is due from work recommended because the history is missing.
- Ask which oil approval and complete filter and plug references will be used.
- Identify the gearbox before agreeing to a transmission service.
- Request an itemised invoice and service-record update after completion.
Clearing a displayed message and resetting the service record are different actions in the manual. A reset on its own does not demonstrate that maintenance has been carried out.
Use the detailed oil and parts guides
Our CLK200 Kompressor oil guide compares the early and later manual tables, explains the 5.5-litre replacement reference and provides a named approved oil example.
The CLK200 Kompressor filter and spark-plug guide covers the shared engine filters, the UK-relevant cabin-filter distinctions and NGK’s engine-number split. Use those references when discussing a service kit with a supplier.
Find more guides in the Mercedes maintenance hub. For warning lamps, gearbox or cabriolet roof faults, see our CLK W209 diagnostic scanner guide.
Sources and applicability
- Mercedes 2004 manual, printed page 265 / PDF page 268: ASSYST and A/B reminders.
- Mercedes 2008 manual, printed pages 206–207 / viewer pages 209–210: A/B service types and battery-disconnected time.
- Mercedes 2004 manual, printed page 416: brake fluid.
- MANN catalogue application: model, engine and output identifiers.
Sources checked 20 October 2026. The English 2004 document is hosted by Mercedes and contains coupé and cabriolet sections. The later reference is Mercedes’s German-language 2008 manual, hosted by ManualsLib. Match the edition, market and supplements supplied with your own car; US-market CLK manuals often cover different engines.
