Code 13: Open O2 Sensor Circuit: Notes

NOTE: Test numbers refer to test numbers on diagnostic chart.

Code 13 will set if the following conditions occur:
- Engine is at operating temperature.
- At least 40 seconds engine running time after start.
- Oxygen signal steady between .35 and .55 volt.
- Throttle position sensor signal greater than idle.
- All conditions must be met for 30 seconds.
If all the above conditions for a Code 13 exist, system will not go into "closed loop".
Determines if the sensor or the wiring is the cause of the Code 13.
When performing this test, use only a high impedance (10-megohm) digital volt/ohmmeter. This test checks the continuity of circuits No. 412 and 413. If circuit No. 413 is open, the ECM voltage on circuit No. 412 will be greater than .6 volt.