P0811
Excessive Clutch A Slippage
The TCM detects more slip across clutch A (the first clutch in dual-clutch boxes, or the launch clutch in automated-manual systems) than the calibration allows. Heat builds up rapidly — risk of glazing the friction discs or warping the pressure plate.
- 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.
- Worn clutch A friction discCommon
- Low clamp force from aged actuatorPossible
Parts involved
- Clutch A
P0811 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.