The 4-wire narrow-band oxygen sensor is a replacement sensor for select 2016-2025 BMW and Toyota applications in the downstream position. It signals whether the exhaust is running rich or lean so the engine computer can trim fuel delivery. A built-in heater brings the element to operating temperature quickly after a cold start.

Walker Products 250-241213 Oxygen Sensor Features:

• Fits 2016-2018 BMW 330e; 2017-2021 BMW 230i, 230i xDrive; 2017-2019 BMW 330i, 330i GT xDrive, 330i xDrive, 740e xDrive, 750i, 750i xDrive, Alpina B7, M760i xDrive
• Fits 2017-2020 BMW 430i, 430i Gran Coupe, 430i xDrive, 430i xDrive Gran Coupe, 530i, 530i xDrive; 2018-2020 BMW 530e, 530e xDrive; 2018-2019 BMW M550i xDrive
• Also fits select BMW and Toyota applications
• Sensor locations by application: B1S2, B2S2 (bank and sensor number)
• 4-wire narrow-band oxygen sensor
• Built-in heater for fast warm-up
• M18x1.5 threaded mounting with a 22 mm hex, 850 mm (33.5 in.) overall length
• Female oblong connector at the harness end with 4 terminal terminals
• Platinum electrode layer with a protective coating against combustion residue