Code 13 - Open Oxygen Sensor Circuit
Code 13 indicates an open in the O2 sensor circuit with the following conditions:
- O2 sensor voltage is within a specified range.
- Above a specified TPS value.
- More than specified time after engine has warmed up.
The ECM supplies about .45 volt between terminals "9" and "14". Voltage may read as low as .32 volt when measured with a 10 megohm digital voltmeter. The O2 sensor varies the voltage within a range of about 1 volt (rich exhaust) to about .1 volt (lean exhaust).
NOTE:
The following step numbers refer to the numbers in the accompanying flow chart(s).
- This test checks to see if problem still exists. Normal dwell reading will vary, indicating fault is not present. Fixed dwell indicates fault.
- By grounding the O2 sensor circuit to the ECM, a "low voltage (lean) signal" is sent to the ECM. This should result in a "full rich (low dwell) command" from the ECM.
- This test checks O2 sensor. With the rich command, O2 sensor should read a high voltage, over .8 volt. If O2 sensor functions, fault is in sensor connections.