An oxygen sensor heater ensures that the oxygen sensor is at the correct temperature to regulate a car’s fuel mixture, states AudiWorld.com. Modern oxygen sensors have this heating element built into the sensor, giving the vehicle the capability to optimize temperature and fuel mixture in under 30 seconds.
In order to function properly, an oxygen sensor must maintain a temperature of approximately 600 degrees Fahrenheit. In older cars, with oxygen sensors that depend on hot exhaust to bring the sensor to temperature, achieving an optimal fuel mixture took minutes. Newer oxygen sensor heaters bring the sensor to temperature much more rapidly, supplying the correct amounts of oxygen and fuel while lowering the amount of pollutants in the exhaust. Oxygen sensor heaters switch on at ignition and remain on as needed to maintain proper temperature.
Many cars with 4-cylinder engines have two oxygen sensors, while 6- and 8-cylinder engines have four sensors, according to Allpar.com. Oxygen sensors are placed before and after the catalytic converter in each bank of cylinders. When oxygen sensor heaters fail, the car’s onboard computer generates error codes indicating which bank has the bad sensor. For example, in 4-cylinder engines, a P0037 code tells mechanics that the oxygen sensor heater at Bank 1, Sensor 2 has an issue with low voltage.