Code 13, Oxygen Sensor Circuit Open Circuit: Notes

The O2 sensor produces a varying voltage as engine reaches normal operating temperature. Voltage will vary from 0-.9 volt. If voltage is more than .45 volt and not varying, this indicates a rich condition. If voltage is less than .45 volt and not varying, this indicates a lean condition.

The O2 sensor does not produce a voltage until it reaches 600°F (316°C). When sensor temperature is less than specified, an open loop condition exists.

1. This ensures O2 sensor is at operating temperature before sensor diagnosis begins.
2. This checks O2 sensor.
3. This indicates when voltage is more than .9 volt and not varying, a short to voltage on O2 sensor circuit is possible.