1. The first oxygen sensor is located in the exhaust manifold.
- This sensor measures the amount of oxygen in the exhaust gas before it enters the catalytic converter.
- The oxygen sensor signal is used by the engine control module (ECM) to adjust the air/fuel mixture.
2. The second oxygen sensor is located in the exhaust pipe after the catalytic converter.
- This sensor measures the amount of oxygen in the exhaust gas after it has passed through the catalytic converter.
- The oxygen sensor signal is used by the ECM to monitor the efficiency of the catalytic converter.