Code 13, Open Oxygen Sensor Circuit: Notes

The O2 sensor is like an open circuit and produces no voltage when its temperature is less than about 600°F (316°C). An open sensor circuit or cold sensor causes "open loop" operation.

1. Code 13 will set at normal operating temperature if at least 2 minutes have passed since engine start, O2 signal voltage is steady between .35-.55 volt and throttle position sensor signal is greater than 7 percent (1200 RPM). All conditions must be met for a precalibrated period of time.
2. This test determines if the O2 sensor, ECM or wiring is at fault.
3. Use only a high-impedance DVOM for this test. This checks for continuity in signal and ground circuits. If ground circuit is open, voltage on signal circuit will be greater than .6 volt.