Question

2003 Volkswagen Beetle Turbo, what is a heated oxygen sensor?

Answer 1

A Oxygen sensor reads the amount of oxygen in the exhaust. The heated O2 sensor has a heater element inside to warm the sensor. The sensor is more effective when it is hot then when it's cold, so they added a heater to make the sensor work faster and better. The sensor reports to the computer and the fuel mixture is adjusted to try and produce more oxygen in the exhaust.