The 4-wire narrow-band oxygen sensor is a replacement sensor for 2007-2012 BMW X3, 2011-2013 BMW 325i, 2011 BMW 528i and 2012 BMW 530i 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 350-34441 Oxygen Sensor Features:

• Fits 2007-2012 BMW X3; 2011-2013 BMW 325i; 2011 BMW 528i; 2012 BMW 530i
• Engine coverage includes 2.5L I6, 3.0L I6 applications
• 4-wire narrow-band oxygen sensor
• Built-in heater for fast warm-up
• M18x1.5 threaded mounting with a 22 mm hex, 375 mm (14.8 in.) overall length
• Male rectangle connector at the harness end
• Platinum electrode layer with a protective coating against combustion residue