Mercedes W205 Cabin Filters: Prefilter, CUK & RHD FP Choices

MANN lists CU 25 002 as a ventilation prefilter/dust separator for the covered W205 C220 d, alongside separate cabin-filter references: CUK 26 023 activated carbon and FP 26 023/1 biofunctional for right-hand drive. CU 25 002 is not simply another name for either of those main cabin-filter choices.

This guide centres on the C220 d/BlueTEC OM651.921, 125 kW/170 hp application. It explains the references and the RHD distinction; it does not assume every car’s service invoice includes every ventilation filter.

Which reference does which job?

Reference	Manufacturer description	Selection point
CU 25 002	Prefilter / dust separator; particulate filter	Separate ventilation prefilter, not the engine air filter.
CUK 26 023	Activated-carbon cabin filter	Main cabin-filter option to match against the car.
FP 26 023/1	Biofunctional cabin filter, right-hand drive	Retain the /1 suffix for the RHD recommendation.
FP 26 023	Biofunctional cabin filter, left-hand drive in the printed catalogue	Do not assume a listing omitting /1 is the same RHD option.

The separate prefilter: CU 25 002

The live MANN page marks the selected C220 d application as a prefilter and dust separator. It describes the mounting position as the engine compartment, passenger side, under the windscreen cowl. Its role is ventilation filtration; it is not the C 22 028 engine intake filter.

Affiliate disclosure: As an Amazon Associate, Unusual Cars earns from qualifying purchases. Shopping links open searches; check the exact item, application, quantity and seller before ordering.

Search Amazon for MANN CU 25 002 prefilters

Check the complete CU 25 002 reference and exact application in the item offered. A photograph of another filter or a generic “pollen filter” description does not tell you which ventilation component a supplier is selling.

CUK 26 023 or FP 26 023/1?

MANN’s CUK product application includes the selected OM651.921 C220 d. Its FP 26 023/1 application explicitly identifies right-hand drive. The printed catalogue distinguishes that FP reference from FP 26 023 for left-hand drive.

Choose between the listed activated-carbon and biofunctional versions after confirming the car’s application. Compare the delivered price for the exact reference.

The links open searches rather than fixed products. Check the full reference, the number supplied and the delivered price. A search result for FP 26 023 without /1 is not the specific RHD product linked here.

What does “cabin filter changed” mean on an invoice?

Ask which reference was fitted. A record of CU 25 002 documents a different item from a record of CUK 26 023 or FP 26 023/1. If a quote simply says “air filter”, also clarify whether it means ventilation or engine intake.

That distinction helps you compare workshop quotes fairly. One may include a prefilter while another includes the main cabin filter; the line-item wording needs to be clear before you compare the prices.

Selection, timing and fitting are separate checks

The parts catalogue establishes an application, not when every filter must be replaced. Use the applicable maintenance schedule and the car’s invoice history to establish what is due. A B-service suffix alone cannot identify a part reference or prove the last replacement.

MANN supplies a mounting-instruction document for the CUK/FP 26 023 family with LHD/RHD distinctions. Check that document and the correct vehicle instructions before attempting access; this page does not replace the illustrated procedure or extend it to the separate prefilter.

For engine filtration, use the W205 C220 d oil and air-filter guide. For the overall service, start with the OM651 service and maintenance overview.

Sources and application notes

Checked 16 October 2026. Match the full manufacturer application and any equipment or steering-side notes before ordering. Catalogue dates describe parts applications, not service intervals.

Browse the Mercedes servicing and maintenance hub or our Mercedes diagnostic scanner guides.

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