Code 13, Oxygen Sensor Circuit Open Circuit: Notes

O2 sensor produces a voltage that varies within a range of about 0.1 volt (lean exhaust) to 1.0 volt (rich exhaust). O2 sensor has a built-in heater that keeps O2 sensor at operating temperature while engine is running. O2 sensor is like an open circuit and produces no voltage when sensor temperature is less than 600°F (316°C), causing an open loop condition.

1. This checks for a short to voltage in Yellow/Blue wire or for a faulty ECM.
2. This checks for a short to ground in Yellow/Blue wire, a faulty ECM or for a faulty O2 sensor.