LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 1990 >> Allante 440T4/ME9 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> ECM DTC EO13: Right O2 Sensor Not Ready >> Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

ECM DTC EO13: Right O2 Sensor Not Ready: Description

The ECM provides a 0.45 volt reference to the oxygen sensor on CKT 412. 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 right oxygen sensor is located in the manifold before the catalytic convertor. 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 EO13. Possible causes of Code EO13 are:

  1. Open in CKT 412 or 413.
  2. Short to voltage on CKT 412 or 413.
  3. Oxygen sensor that cannot respond.