All Supras and 1982-85 Celicas are equipped with an oxygen sensor warning light on the instrument panel. The light may go on when the car is started, then it should go out. If the light stays on, check your odometer. The light is connected up to an elapsed mileage counter which turns the light on every 30,000 miles (48,270 km). This is your signal that it is time to replace the oxygen sensor and have the entire system checked out. After replacement of the sensor, the elapsed mileage counter must be reset.
- Locate the counter. It can be found under the left side of the instrument panel, on the brake pedal bracket.
- Unscrew the mounting bolt, disconnect the wiring harness and remove the counter.
- Remove the bolt on top of the counter.
- Lift off the counter cover and push the reset switch.
- Installation is in the reverse order of removal.