Peugeot 408 Automatic Transmission Issues

Strange shifting and the light coming on definitely points to something going wrong with your automatic transmission. Since you checked the fluid, that's a good start. But "okay" fluid level doesn't mean the fluid itself is healthy. How old is the hydraulic fluid? Have you ever had a transmission flush done? Old fluid can seriously mess with transmission performance and cause the symptoms you're describing. It might be worth considering a transmission flush and new transmission oil to see if that helps before you start looking at more serious, expensive problems.

Thanks for the quick reply! I'm not sure when the hydraulic fluid was last changed, to be honest. I've only had the car for a couple of years. If it's just old fluid, would that really cause it to go into emergency mode sometimes? And why would that trigger the transmission light?

Absolutely, old fluid can cause all sorts of havoc! Think of it like this: the hydraulic fluid is what allows your transmission to properly engage and disengage gears. Over time, it gets contaminated with debris and loses its lubricating properties, which can lead to erratic shifting and even cause the transmission to overheat. The emergency mode is the car's way of protecting itself from further damage when it detects something is seriously wrong. And yes, that can definitely trigger the transmission light. However, if you haven't changed the fluid in ages, and it’s still acting up after a flush, undervoltage in the vehicle may be the issue. At this point, I recommend visiting a workshop.

Thanks again for the advice! I took it to the shop, and you were right – it was the transmission oil! They did a flush and replaced the fluid, and it's shifting smoothly again. Cost me 240€, but well worth it to avoid bigger problems down the road.