Mercedes-Benz B-Class Oxygen Sensor Replacement Parts

Yes, but only on petrol-engined B-Class models — the W245 (2005–2011) and W246 (2011–2018) petrol variants carry lambda/oxygen sensors as part of the exhaust management system. Diesel B-Class models use a different emissions strategy and do not have a conventional oxygen sensor in the same way, relying instead on NOx and other sensors; if you have a diesel, confirm with the breaker exactly what sensor your car needs. If you have a petrol B-Class, the engine code is the key piece of information to have ready when sourcing a used sensor.

Almost certainly not as a direct swap — the W245 ran from 2005 to 2011 and the W246 is a completely different generation from 2011 to 2018, with different engines, exhaust layouts, and sensor connectors. Engine codes differ across these two generations even where displacement looks similar on paper, so the sensor position, thread size, and wiring plug are unlikely to match. Always match the part to your specific generation and engine code, and confirm with the breaker before buying.

No — trim level does not affect which oxygen sensor your B-Class needs; Sport, SE, Executive, and AMG Line models all share the same exhaust system when they share the same engine code. The sensor is determined entirely by the engine code and model year, not by any trim-specific equipment. That said, be aware that AMG Line badges do not indicate a different engine on standard B-Class models, so the same rule applies.

The W246 received a facelift around 2014-2015, and while the visual changes were mostly cosmetic, there were some engine and emissions updates across the range that could affect sensor specification. Whether a pre-facelift sensor crosses over to a post-facelift car depends on your specific engine code and any changes made to that unit at the facelift — this is strong confirm-with-breaker territory. Give the breaker your full registration and engine code to be sure.

Yes, it can — emissions era matters because engine management calibration, sensor count, and sensor positioning can differ between Euro 5 and Euro 6 variants even on the same engine family. The W246 B-Class straddled Euro 5 and Euro 6 during its production run, so a sensor from an earlier car may not be correct for a later Euro 6 example even if the engine displacement looks the same. Check your registration against your V5C for the Euro standard, and give that information to the breaker alongside your engine code.

Petrol B-Class models typically have at least two oxygen sensors — one upstream of the catalytic converter (pre-cat) and one downstream (post-cat) — and these are different parts with different part numbers, so you need to know which one has failed before ordering. Your diagnostic fault code should indicate whether it is the upstream or downstream sensor; if you are unsure, ask a garage to read the codes before approaching a breaker. Confirm the exact position and engine code with the breaker to avoid ordering the wrong sensor.