Oxygen (O2) Sensor

Oxygen sensor detects oxygen content of exhaust gases and sends signal to ECU, which varies air/fuel ratio to maintain a 14.7:1 ratio under most conditions. This ratio is most efficient for combustion and catalytic converter operation.

Prelude and Civic (except D15Z1) use heated oxygen sensors. Civic with D15Z1 engine uses a heated Linear Air/Fuel ratio (LAF) sensor which performs the same function as an oxygen sensor but over a wider range. Accord uses a non-heated oxygen sensor.