Auto transmission fourth gear incorrect ratio

I don't have any information for your model, but it sounds like you have a version of the computer-controlled transmission first developed by Chrysler. The most common cause of gear ratio error fault codes is excessive slippage in a clutch pack, due to wear and high mileage. The second cause is a problem with one of the speed sensor circuits.

With the Chrysler system, this type of fault code sends it into "limp" mode where it stays in second gear. You have to stop the engine, then turn the ignition switch back on to get it out of limp mode. You can often get an idea of the cause of this code by observing when it sets, and / or goes into limp mode. If there's an electrical problem with a sensor circuit, like a cut wire or corroded connector terminal, that will be detected right away when the engine is first started. If slippage is occurring in a clutch pack, the transmission will start out in first gear, like normal, and up-shift like normal, until that clutch pack engages that has the excessive slippage. That is when it will be detected and set that code.

Skoda = VW based normally. This should be a ZF 01V transmission. They used the same trans in a lot of Audi and VW cars.

Most likely reason for that code is that clutch pack E is failing to apply fully. That pack only activates for 4th gear which is also 1:1 ratio and the default limp home gear.

The Skoda brand is owned by Volkswagen and they use many of the same parts across the various brands and models.
The Tiptronic ZF 01V transmission in your vehicle is used in many other vehicles they sell, they just alter the programming to match the vehicle.

The issue is still that the E clutch pack is failing.