On occasions since it was new the engine light on my 2007 Mazda BT-50 diesel comes on. A number of Mazda dealers I have taken it to have assured me they have fixed it, but it still occurs. They put it on the computer to locate any error codes and reset it. It has never affected the performance or driving of the vehicle even while towing our caravan. The light will go off after a period of time. Any ideas?
It could be the diesel particulate filter alerting you that it's doing its thing. DPFs regularly go through a regeneration process, and most do it while you're driving along without any real impact on the performance of the car.