The 4-wire narrow-band oxygen sensor is a replacement sensor for select 2004-2005 Buick, Chevy, GMC, Isuzu and other 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 350-34047 Oxygen Sensor Features:

• Fits 2004-2005 Buick Rainier, Chevy Colorado, Trailblazer, Trailblazer EXT, GMC Canyon, Envoy, Envoy XL, Envoy XUV, Isuzu Ascender; 2004 Oldsmobile Bravada
• Fits 2005 Saab 9-7x
• Engine coverage includes 2.8L I4, 3.5L I5, 4.2L I6 applications
• Sensor location by application: B1S1 (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, 480 mm (18.9 in.) overall length
• Female trapezoid connector at the harness end
• Platinum electrode layer with a protective coating against combustion residue