Code 13, Rear/Bank 1 Open Oxygen - Sensor Circuit: Notes

Code 13 will set if Code 14, 15, 21, 22, 26, 27 or 119 is not set, engine is running, RPM is greater than 800, engine is at operating temperature, Bank 1 sensor voltage is steady at .3-.6 volt, throttle switch is open, throttle angle is 5.4-25.0 degrees and all conditions have been met for at least 64 seconds. When Code 13 is set, PCM will use Bank 2 sensor for fuel control.

1. Scan tester Bank 1 oxygen sensor voltage should fluctuate above .6 volt and below .3 volt. If voltage remains above .6 volt, check Bank 1 signal high circuit for short to voltage. If voltage remains below .3 volt, check signal high circuit for short to ground.
2. Measuring voltage with a DVOM will isolate a sensor/wiring problem from a PCM problem. If voltage fluctuates above .6 volt and below .3 volt, fault is with the PCM. If voltage remains below .3 volt check signal high circuit for short to ground or sensor low (ground) for short to voltage. If voltage remains greater than .6 volt, check Bank 1 sensor signal high circuit for short to voltage. If voltage remains between .3 volt and .6 volt, check signal high and signal low circuits for an open.