An oxygen sensor detects the amount of oxygen in vehicle's exhaust gases and sends a signal to the engine computer. This signal is used by the engine ECU to fine-tune the air/fuel mixture to the optimal level to ensure maximum catalyst efficiency and a long service life. A worn-out oxygen sensor can cause serious problems like excessive fuel consumption and elevated exhaust emissions as well as shorten the life of a catalytic converter and affect engine performance. Bosch oxygen sensors are the number one choice for many car makers worldwide. Each oxygen sensor by Bosch is subjected to a 1,000 degree Celsius functional test and a leak test to ensure environmental and functional robustness. Bosch oxygen sensors feature a revolutionary Bosch patented universal connection system that is fully submersible in water and protects against contamination as well as withstands extreme temperatures and engine vibration.