2003 Lexus ES300 Q&A
2003 Lexus ES300 Question: diagnosis ,either AF sensor or oxy sensor defective. How to find which one?
It's the same thing! The upstream sensors..(02 sensors).. are sometimes called Air/Fuel sensors because that is what they monitor before the exhaust enters the catalytic converter...... the downstream sensors are called 02 sensors because they monitor the oxygen content of the exhaust as it leaves the catalytic converter...they are the same but have different task! The front sensors have a different part number than the rear... and are not interchangeable! ... Order either FRONT...... OR...... REAR 02 sensors and you will get the right part! .. In your case it is the FRONT....hope this helps . - pushrod