Used Mercedes-Benz B-Class Catalytic Converter

Both years fall within the second-generation B-Class (W246, 2011–2018), so they share the same platform, but fitment of a used catalytic converter depends heavily on matching the exact engine code and emissions standard — the W246 range included petrol and diesel variants across Euro 5 and Euro 6 eras, and the boundary between those standards falls within the W246's production run. Name the generation boundary to the breaker and ask them to confirm the part against your specific registration before buying.

The W245 (2005–2011) and W246 (2011–2018) are entirely different generations with different engines, exhaust layouts, and emissions standards, so a catalytic converter from one will not cross to the other. This is a firm generation boundary, not just a trim difference, and no fitment guidance suggests interchangeability across it. Source a part from the correct generation and confirm the engine code with the breaker against your registration.

Trim level does not determine catalytic converter fitment on the B-Class — what matters is the engine code, fuel type (petrol or diesel), and the emissions standard applicable to your car's registration year. An SE and an AMG Line on the same engine and same year would use the same catalytic converter. You may find minor exhaust system differences in appearance between trims, but the cat itself follows the engine, not the badge.

Petrol-engined B-Class models have a traditional catalytic converter as part of their exhaust aftertreatment system; diesel-engined variants primarily use a Diesel Particulate Filter (DPF) and may also incorporate a diesel oxidation catalyst (DOC) depending on the specific engine and emissions spec. Whether your diesel B-Class needs a standalone cat or a combined unit is strong confirm-with-breaker territory — supply your registration to the breaker so they can check the exact part for your engine code and Euro standard.

The shift from Euro 5 to Euro 6 occurred around September 2015 for new registrations in the UK, so a 2015 B-Class diesel could be either standard depending on when it was first registered. This matters significantly because exhaust aftertreatment components are not interchangeable across Euro standards — fitting a part from the wrong emissions era can cause an MOT failure or warning lights. Always confirm the exact emissions standard for your registration with the breaker before agreeing a purchase.

The W246 received a facelift in 2014 which brought updates to some engines and equipment, and while both sit within the same generation, whether the catalytic converter changed across that facelift depends on the specific engine code and any associated emissions spec changes. The generation name is the same, but crossing a facelift boundary on exhaust aftertreatment parts is territory where you should confirm directly with the breaker — give them your registration and they can check whether the donor vehicle's part is a genuine match for your pre- or post-facelift engine.