Review on Denso 234 9015 Fuel Ratio Sensor by Andrew Agarwal

This was a perfect addition to my 2004 Subaru Forester XS. This is the OEM part of the sensor on the front of the transmitter. Two functions are assigned to this sensor. One is the heater, which helps the sensor do its job while the exhaust gases heat up, and the other is the actual sensor, which sends information about the air-fuel mixture to the on-board computer. If the preheat function has failed (which it often does), the vehicle will function normally after warming up a bit. When the air/fuel mixture function fails, the vehicle often runs erratically.