The oxygen sensor installs in the downstream position on select 1995-2003 BMW applications. 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 350-34045 Oxygen Sensor Features:

• Fits 1995-1998 BMW 750iL; 1995-1999 BMW 850Ci; 1996-2001 BMW 740iL; 1996-1997 BMW 840Ci; 1996-1998 BMW Z3; 1997-2003 BMW 540i; 1997-2001 BMW 740i; 1999-2003 BMW M5
• Fits 2000-2003 BMW Z8
• Engine coverage includes 1.9L I4, 4.4L V8, 4.8L V8, 4.9L V8, 5.0L V8, 5.4L V12 applications
• 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, 555 mm (21.9 in.) overall length
• Female circle connector at the harness end with 4 bullet terminals
• Platinum electrode layer with a protective coating against combustion residue