Koleos Driver Seat Heater Failure

The error code suggests a fault within the seat heating system itself. Have you considered testing the resistance of the heating element within the seat? A break in the element could certainly cause the symptoms you describe and trigger an error in the system's diagnostic memory.

Thanks for the tip! I hadn't thought about directly testing the heating element's resistance. Where exactly is that heating element located within the seat? Is it easy to access, or am I looking at a complete seat disassembly job?

The heating element is typically integrated within the seat cushion itself. Access often requires partial disassembly of the seat, including removal of the upholstery. Given the potential for airbag involvement in the seat structure, and the diagnostic evidence of a defective heating mat itself, consider consulting a qualified workshop. Direct replacement of the heating mat will likely be required. This is a quite common issue.

I took your advice and brought it to a shop. They confirmed it was indeed the heating mat. The final repair cost 390€, including the part and labor. Ouch, but at least my bum will be warm again! Thanks for steering me in the right direction!