The oxygen sensor installs in the downstream position on 2001-2003 Infiniti QX4, 2002-2004 Infiniti I35, 2001-2002 Nissan Pathfinder, Sentra and 2002-2003 Nissan Maxima. 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 350-34290 Oxygen Sensor Features:

• Fits 2001-2003 Infiniti QX4; 2002-2004 Infiniti I35; 2001-2002 Nissan Pathfinder, Sentra; 2002-2003 Nissan Maxima
• Engine coverage includes 1.8L I4, 3.5L V6 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, 900 mm (35.4 in.) overall length
• Male square connector at the harness end
• Platinum electrode layer with a protective coating against combustion residue