Pcm Code E13, Oxygen (O2) Sensor Not Ready: Description

WARNING: This page is about a different car, the 1992 Cadillac Fleetwood and 1992 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.

PCM provides a .45-volt reference to O2 sensor on circuit No. 412. When warm, a properly operating O2 sensor will drive .45-volt reference lower to indicate lean mixtures and higher to indicate a rich mixture. If O2 sensor does not vary from COLD or NOT READY voltage under test conditions, PCM assumes sensor cannot respond to rich or lean air/fuel mixtures. Code E13 is then set. Possible causes of Code E13 are:

Open or short on circuit No. 412 or 413.
O2 sensor faulty.