* Upstream O2 Sensor (before the catalytic converter): This sensor is usually located in the exhaust manifold, fairly close to the engine. You'll likely find it near the front of the engine compartment, on one of the exhaust manifold pipes. It's often threaded into the manifold.
* Downstream O2 Sensor (after the catalytic converter): This sensor is located in the exhaust pipe after the catalytic converter. This one is typically easier to access, usually closer to the rear of the vehicle but still under the car.
To be absolutely certain:
1. Consult your vehicle's repair manual: This is the most reliable source for precise location information, including diagrams.
2. Use a vehicle-specific online parts diagram: Many auto parts websites (like AutoZone, Advance Auto Parts, etc.) allow you to search by year, make, and model and view detailed diagrams showing the location of all parts, including O2 sensors.
Looking at a parts diagram online is generally the easiest and safest approach before you begin working under the car. Remember to always disconnect the negative battery terminal before working on any electrical components.
