Koleos reduced engine power error code

Reduced power and a stored error code often point to several possibilities. Has the car had any aftermarket modifications, like a chip tune, installed?

Yes, the car did receive a chip tuning modification from a third-party provider some time ago. Could that be the primary cause of the engine issue?

Faulty chip tuning is a very likely culprit, especially given the symptoms. These modifications don't always play well with the factory ECU. It is something a workshop should check.

The chip tuning was indeed faulty and caused the error. The repair, which involved reflashing the ECU, cost 180€.