Mercedes-Benz Citan Lambda Sensor Replacement Parts

The Citan was sold in the UK predominantly with diesel engines (the 108 CDI, 109 CDI, 111 CDI, and 113 CDI variants), and diesel engines do not use a traditional lambda sensor in the same way petrol engines do — they use NOx sensors and exhaust temperature sensors instead. If your Citan is one of the rarer petrol-engined variants (the 108 or 111 with a petrol unit), a lambda sensor will be present, as petrol engines rely on one for fuelling and emissions control. If you have a diesel Citan and have been quoted for a lambda sensor, it is worth double-checking whether the part you actually need is a NOx sensor or an exhaust temperature sensor — confirm the exact part against your registration with the breaker.

The original Citan ran as the W415 from 2012 until 2021, when it was replaced by the all-new W420 generation; these are fundamentally different vehicles built on different platforms and with different engine families, so parts from one generation will not transfer to the other. If your petrol Citan is a W415, make sure any lambda sensor you source is also from a W415 with the matching engine code, and likewise for the W420. Always confirm the engine code and year against your registration with the breaker before buying.

No — trim level has no bearing on lambda sensor fitment for the Citan. The Citan was sold in trims including Base, SE, and Sport, but none of these trims changed the engine or exhaust configuration, so the sensor is determined entirely by engine code and emissions standard, not by which trim you have. The appearance of the vehicle may differ between trims but the underbonnet specification relevant to the lambda sensor does not, so focus on matching the engine code rather than the trim name when sourcing a used part.

Yes, this matters significantly — the W415 Citan spanned the Euro 5 to Euro 6 transition, and the exhaust and emissions hardware changed accordingly. A lambda sensor from a Euro 5 petrol Citan may not be compatible with a Euro 6 car, and fitting the wrong sensor could cause running problems or an MOT failure. Confirm the exact emissions standard of your vehicle against your registration with the breaker, and make sure the donor vehicle matches on this point.

They are not the same thing — a lambda (oxygen) sensor measures exhaust oxygen content for fuelling on petrol engines, whereas a NOx sensor on a diesel measures nitrogen oxide levels to manage the SCR or exhaust aftertreatment system. On a diesel Citan, the NOx sensor is the correct part to be looking for, not a lambda sensor. Confirm the exact sensor type and its position in the exhaust system (pre- or post-catalyst) with the breaker against your registration to make sure you get the right unit.