This 4-wire narrow-band oxygen sensor fits select 2006-2026 BMW and Chirey applications and 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 350-34621 Oxygen Sensor Features:

• Fits 2006-2010 BMW 130i; 2006-2013 BMW 325i; 2006 BMW 325xi, 330xi; 2006-2007 BMW 330i; 2006-2016 BMW 550i, 750i, Z4; 2006-2011 BMW 650Ci; 2006-2018 BMW 650i
• Fits 2006-2015 BMW 750Li; 2007-2013 BMW 328i; 2007-2008 BMW 328xi, 335xi; 2007-2010 BMW 335i, X3; 2007-2018 BMW X5; 2008-2013 BMW 125i, 128i
• Also fits select BMW and Chirey applications
• Sensor locations by application: B1S1, B1S2, B2S2 (bank and sensor number)
• Used in both upstream and downstream positions, depending on application
• 4-wire narrow-band oxygen sensor
• Built-in heater for fast warm-up
• M18x1.5 threaded mounting with a 22 mm hex, 600 mm (23.6 in.) overall length
• Male circle connector at the harness end
• Platinum electrode layer with a protective coating against combustion residue