P28EC
Shift Motor Position Sensor Exceeded Learning Limit
The required adaptation offset for the shift motor position sensor exceeds the calibrated learning window. Sensor or mechanism out of nominal range.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Common causes
Ordered by how often each turns out to be the cause.
- Mechanical wear shifted end-stopsCommon
- Sensor reference driftedPossible
Parts involved
- Shift Motor
- Shift Motor Position Sensor
- TCM
P28EC is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.