Used BMW 3 Series Air Flow Meter

No — air flow meters (also called mass air flow sensors or MAF sensors) are fitted to petrol engines that use them for fuelling calculations, but not every 3 Series engine variant uses one; some diesel engines rely on a MAP sensor instead, and fitment varies by engine code and generation. Before searching for a used unit, confirm your exact engine code (shown on your V5 logbook or a VIN check) so you and the breaker are looking for the right thing. If you are unsure whether your specific engine uses a MAF sensor, the breaker can confirm against your registration.

Almost certainly not — the E46 ran from 1998 to 2006 and the E90 from 2005 to 2012, and although there is a brief overlap year, the two generations used substantially different engine families with different sensor specifications and connectors. Engine code is the key detail here: even if two cars share a similar displacement or badge, a different engine code means a different MAF unit. Always give the breaker both engine codes so they can check compatibility rather than going on generation alone.

No — SE, M Sport, Sport, and other 3 Series trim levels are largely cosmetic packages and do not change the engine or its air flow meter; what matters is the engine code, which is the same regardless of trim on identically engined cars. An M Sport badge does not mean an M engine, so unless your car is an actual M3 with a distinct engine code, the trim name is irrelevant to this part. Confirm your engine code and fuel type with the breaker and ignore the trim label when sourcing the sensor.

The E90 received a facelift in 2008 which brought some engine and ancillary updates, so while the generation name is the same, a sensor from a pre-facelift car may not be a straight swap onto a post-facelift one even if the engine code looks similar. The engine code is the safest guide — if both cars share the exact same code the chances of compatibility are much higher, but you should still confirm with the breaker against your full registration, as connector and mounting details can change mid-production run.

Many BMW diesel engines, including some 320d variants, do use a MAF sensor as part of their air management system, but this is not universal across every generation of the 320d engine. The engine code on your V5 is the most reliable way to establish whether your specific unit uses one, and the breaker can confirm whether a used MAF is the correct part for your car or whether a MAP sensor is what you actually need. Do not assume the same answer applies across different 320d generations, as the engine was significantly revised between the E46, E90 (N47 family), and F30 eras.

The F30 saloon ran from 2012 to 2019 and the F34 Gran Turismo covered a similar period — body style does not affect which air flow meter is fitted, so if both cars share the same engine code the sensor is likely the same unit. The F34 is simply a different body style on broadly the same platform, and the MAF sensor follows the engine, not the bodywork. Confirm the engine codes match and check with the breaker against both registrations before buying, as ancillary details can differ even between identically badged variants.