Code 13: Open Oxygen Sensor Circuit: Notes

1. Code 13 will set when the following conditions occur:
   • Engine at normal operating temperature.
   • At least 2 minutes elapsed since start-up.
   • Oxygen signal voltage steady between .35 and .55 volt.
   • Throttle angle greater than 3-6 percent (about .3 volt greater than closed throttle voltage).
   • All conditions must be met for about 60 seconds.

If conditions for a Code 13 exist, the system will not go "closed loop".

2) This test determines if the sensor, wiring or ECM is the cause of Code 13.

3) When conducting this test, use only a high impedance (10-megohm) digital volt-ohmmeter. This tests the continuity of the sensor signal and ground circuits. If ground circuit is open, the ECM voltage on the signal circuit will be greater than .6 volt.