ECM DTC EO17: Left O2 Sensor Not Ready: Description

The ECM provides a 0.45 volt reference to the oxygen sensor on CKT 912. When the oxygen sensor reaches operating temperature it will generate a counter voltage that will vary based on the amount of oxygen in the exhaust. The left Oxygen sensor is located in the manifold just behind the cooling fan. A lean exhaust will generate a low voltage and cause the .45 reference to move lower. A rich exhaust will generate a high voltage and cause the .45 reference to move higher. If the oxygen sensor can't respond under the test conditions and generate a voltage greater or less than the .45 reference, it will set a code EO17. Possible causes of Code EO17 are:

1. Open in CKT 912 or 413.
2. Short to voltage on CKT 912 or 413.
3. Oxygen sensor that cannot respond.