The oxygen sensor installs in the downstream position on 2012-2015 BMW 118i with the 1.6L I4 engine. 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 250-241090 Oxygen Sensor Features:

• Fits 2012-2015 BMW 118i with the 1.6L I4 engine
• Sensor location by application: B1S2 (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, 700 mm (27.6 in.) overall length
• Female rectangle connector at the harness end with 4 spade terminals
• Platinum electrode layer with a protective coating against combustion residue