Why Does My DualSense Left Stick Drift Upward When I Am Not Touching It?

Your reading is the useful part of this, so let me start there. A healthy DualSense stick rests between -0.03 and +0.03 on both axes. Anything inside that is normal sensor noise. At -0.18 your potentiometer is reporting almost a fifth of a full stick push while the stick is physically centred, and that is not a setting that has drifted out of place. It is the carbon track inside the sensor wearing thin where your thumb rests most, which is why it is only the left stick and only one direction.

That matters because it decides whether cleaning is worth your time. Isopropyl alcohol genuinely does fix a slice of drift cases, the ones caused by dust or dried drink bridging the contacts, and those usually read between -0.05 and -0.10 and come and go. Wear-related drift like yours is one-directional, steady, and gets worse month by month. You can clean it and you may see the number improve for two or three weeks, but it will come back and it will come back worse.

The honest answer is that this controller needs a new left stick module. That is a genuinely cheap part and the job is a well-documented one, or any repair shop will do it. What is not worth doing is raising the in-game deadzone to hide it, which is the advice you will see everywhere. It works for about a month and costs you precision in every game you play, because you are telling the game to ignore real small inputs as well as the false one.