Used Mercedes-Benz GLA Oxygen Sensor

Oxygen sensors (lambda sensors) exist on petrol-engined GLA models, where they monitor exhaust gases before and after the catalytic converter to help the ECU manage fuelling. Diesel GLAs use a different emissions strategy centred on NOx sensors, a diesel oxidation catalyst, and a DPF rather than a traditional wideband lambda sensor, so if your GLA is diesel you are likely looking for a NOx sensor or exhaust temperature sensor instead. Check your fuel type and engine code before ordering, as the two systems are not interchangeable.

The GLA X156 ran from 2013 to 2019, with a facelift arriving in 2017 that brought revised bumpers and interior updates but no fundamental engine changes for most variants – the same M270 and M133 petrol engine family carried across. For the same engine code on the same side of the cat (pre-cat or post-cat), fitment is broadly likely to remain consistent across that facelift boundary, but you should confirm the exact connector type and sensor position with the breaker against your registration, as part numbers can differ between build dates even within the same generation.

The H247, launched in 2020, is a different platform entirely with a new engine family, revised exhaust architecture, and tighter Euro 6d emissions calibration compared with the Euro 6 and Euro 5 variants in the X156 range. Sensor connectors, thread sizes, and ECU calibration expectations differ between the two generations, so a direct swap is very unlikely to work correctly. Treat these as separate parts and source from the matching generation; confirm the specific part number with the breaker against your registration.

Both the GLA 200 and GLA 250 in the X156 generation use petrol engines from the M270 family, but the GLA 250 runs a higher-output tune with different fuelling maps, which can mean different sensor part numbers even though the physical sensor may look identical. The trim level – Sport, AMG Line, Executive, and so on – makes no difference to which sensor you need; it is the engine code and emissions standard that matter. Always give the breaker your engine code and registration so they can match the correct sensor rather than going on displacement alone.

No – trim level is irrelevant to oxygen sensor fitment on the GLA; AMG Line, SE, and Sport are cosmetic and equipment packages rather than mechanical variants. The sensor you need is determined entirely by your engine code, fuel type, and the emissions standard your vehicle was built to, not by which badge is on the tailgate. A breaker may quote you a sensor from any trim level provided the engine code and generation match your car.

Euro 5 and Euro 6 GLAs can share the same physical engine family but are calibrated differently, and the post-cat sensor in particular is tuned to work with catalytic converters and ECU maps specific to each emissions era; fitting a sensor from the wrong era risks incorrect fuelling feedback or an emissions-related fault code. The interaction between the oxygen sensor, catalytic converter, and ECU mapping is strong confirm-with-breaker territory – give the breaker your registration and engine code and ask them to match the emissions standard as well as the engine code before supplying the part.