Where is the oxygen sensor located on the old Jetta?
2 Answers
The old Jetta has two oxygen sensors, one located at the position where the exhaust pipe exits the engine and another behind the three-way catalytic converter, referred to as the front and rear oxygen sensors. The oxygen sensor primarily detects the oxygen content in the exhaust, and the ECU adjusts the fuel injection quantity based on the data it transmits. There is no difference in structure or working principle between the front and rear oxygen sensors. Below is some relevant information about automotive oxygen sensors: The automotive oxygen sensor is a critical feedback sensor in the electronic fuel injection engine control system. It is a key component in controlling vehicle exhaust emissions, reducing environmental pollution caused by vehicles, and improving the fuel combustion quality of the vehicle engine. There are two types of oxygen sensors: zirconium dioxide and titanium dioxide.
When we talk about the old Jetta, the position of the oxygen sensor is really crucial. I often see it installed at the front of the exhaust pipe, near the exhaust manifold, because it needs to detect the oxygen content in the exhaust gases as quickly as possible to control fuel injection. If you're into DIY car repairs, you can spot it plugged into the pipe under the car, with wires connected to the computer module. In older models, like some Jettas from the 1990s, this area is prone to rust. If it gets clogged or short-circuited, the engine light will come on, and power will drop. So, I recommend cleaning off dust during regular maintenance and using a diagnostic tool to read fault codes to prevent issues. Replacing it isn't complicated—just unplug the connector and unscrew the bolts—but it's best to use a pit or lift for safety. In short, its position greatly affects emissions performance, so don't overlook this small part.
