Peugeot 4008 Automatic Transmission Problems

Sounds like a potential issue with the automatic transmission oil or the transmission control module. When was the last time you had the transmission fluid checked or changed? Low fluid level or degraded fluid can definitely cause those symptoms. The emergency mode activation suggests the system is detecting a significant fault. It could also be related to undervoltage, which can cause the transmission control module to act erratically. Have you scanned the car for any diagnostic trouble codes (DTCs)? That would be the first step in troubleshooting this.

I haven't checked the transmission fluid recently. How would undervoltage affect the transmission?

Undervoltage can cause all sorts of weird issues with electronic control units (ECUs), including the transmission control module (TCM). Modern automatic transmissions rely heavily on precise electronic control of solenoids and sensors. A voltage drop can cause the TCM to misinterpret sensor signals or send incorrect commands to the transmission, leading to shifting problems and potentially triggering the emergency mode. While you can check the fluid yourself, given the symptoms and the potential electrical connection, it's best to have a workshop check the oil level and its general condition in case there are any leaks. Also a proper diagnostic scan with a capable scan tool should be performed to check for logged errors.

Thanks for the detailed advice. I took it to a workshop and they found the transmission oil was worn out and there was indeed an undervoltage issue. They did a transmission flush and fixed the electrical problem. Total cost was 240€. Shifting is smooth again now.