This 4-wire narrow-band oxygen sensor fits select 2003-2017 Buick, Cadillac, Chevy, GMC and other applications and 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 350-34581 Oxygen Sensor Features:

• Fits 2005-2009 Buick Allure, LaCrosse, Chevy Equinox, Uplander, Pontiac Montana
• Fits 2005 Buick Rainier, Cadillac DeVille, Chevy SSR, Trailblazer EXT, GMC Envoy, Envoy XL, Envoy XUV, Isuzu Ascender, Saab 9-7x
• Also fits select Buick, Cadillac, Chevy, GMC, Isuzu, Pontiac, Saab and Saturn applications
• Sensor locations by application: B1S1, B1S2, B2S1, B2S2 (bank and sensor number)
• Used in both upstream and downstream positions, depending on application
• 4-wire narrow-band oxygen sensor
• Built-in heater for fast warm-up
• M18x1.5 threaded mounting with a 22 mm hex, 420 mm (16.5 in.) overall length
• Female square connector at the harness end
• Platinum electrode layer with a protective coating against combustion residue