Bipper Overheating Check Engine Light

Overheating and the check engine light are definitely cause for concern. It's possible a faulty speed sensor could be involved, as that can affect temperature control. Have you checked the fan blade itself for any obstruction or damage? What about the fan motor – is it running at all?

I've checked the fan blade; no obstructions or damage. The fan motor doesn't run, even when the engine is hot. Could a faulty thermal switch cause this? Where is the switch located?

A faulty thermal switch is indeed plausible. Given the symptoms, it would be prudent to have the vehicle inspected by a qualified technician. It is difficult to say where the switch is located without seeing the vehicle. Further diagnosis is recommended.

I'll schedule a professional inspection. The estimated repair cost is about 250€, which seems reasonable given the potential for further damage.