Knock sensor is designed to detect when the combustion in car is not being properly controlled.A knock sensor uses an internal element that is extremely accurate to vibration and will detect when the pressure wave from the combustion hits the cylinder wall before it is supposed to.When the sensor detects incorrect noise from internals of the motor it will retard the timing in order to maintain the engine.The sensor has been designed to act as if mechanic was listening to the engine and keeping an eye on the things for the driver.

Notice :
Please find the amazon fitment on the top of the page,enter your vehicle information to check if the item fit your vehicle

Fitment:
2006 for Buick Lucerne 4.6L
2004-2005 for Buick Rainier 4.2L
2003-2005 for Cadillac DeVille 4.6L
2006 for Cadillac DTS 4.6L
2003-2004 for Cadillac Seville 4.6L
2004-2006 for Cadillac SRX 4.6L
2005-2006 for Cadillac STS 4.6L
2004-2006 for Cadillac XLR 4.6L
2004-2006 for Chevrolet Colorado 2.8L
2004-2006 for Chevrolet Colorado 3.5L
2003-2005 for Chevrolet Trailblazer 4.2L
2003-2005 for Chevrolet Trailblazer EXT 4.2L
2004-2006 for GMC Canyon 2.8L
2004-2006 for GMC Canyon 3.5L
2003-2005 for GMC Envoy 4.2L
2003-2005 for GMC Envoy XL 4.2L
2004-2005 for GMC Envoy XUV 4.2L
2006 for Hummer H3 3.5L
2003-2005 for Isuzu Ascender 4.2L
2006 for Isuzu i-280 2.8L
2006 for Isuzu i-350 3.5L
2003 for Oldsmobile Aurora 4.0L
2003-2004 for Oldsmobile Bravada 4.2L
2004-2005 for Pontiac Bonneville 4.6L
2005 for Saab 9-7x 4.2L