Bosch oxygen (lambda) sensor for the BMW B46/B48 2.0L turbo engine family. It sits in the exhaust stream ahead of (or after) the catalytic converter and continuously reports the air-fuel ratio to the DME, letting the engine trim fueling for efficiency, emissions compliance and catalytic-converter protection. A failing sensor typically shows up as a rough idle, poor fuel economy, a check-engine light, or a failed emissions test.

Fitment: BMW B46/B48 2.0L turbo models across F20/F30/G20/G30 chassis - 1 Series, 2 Series, 3 Series, 4 Series and 5 Series (confirm exact engine code/position at checkout).