You have to remember the sensors are just inputting data to the PCM. If the sensor is reading within its programmed limits the PCM just thinks the reading is accurate and makes the necessary adjustments. Codes set when readings are out of range, not varying like they should, or not as expected based on other inputs. When
@jos51700 temp was reading 17 degrees, that is perfectly normal. Heck, it's five degrees here in Michigan right now. So that is in an acceptable range even though it was way too low and caused a rich condition.
