The 4-wire narrow-band oxygen sensor is a replacement sensor for select 2000-2005 Audi and Volkswagen applications in the upstream 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 350-34144 Oxygen Sensor Features:

• Fits 2000-2001 Audi A4, A4 Quattro, A6; 2000-2004 Audi A6 Quattro; 2000-2002 Audi S4; 2001 Audi Allroad Quattro; 2002 Audi RS4; 2002-2003 Audi S6
• Fits 2000-2005 Volkswagen Passat
• Engine coverage includes 2.7L V6, 2.8L V6, 4.2L V8 applications
• 4-wire narrow-band oxygen sensor
• Built-in heater for fast warm-up
• M18x1.5 threaded mounting with a 22 mm hex, 620 mm (24.4 in.) overall length
• Male rectangle connector at the harness end with 4 spade terminals
• Platinum electrode layer with a protective coating against combustion residue