Whats the average mileage that a Dodge Durango's engine will turn the engine light on?
There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.
The "Dodge" diesel is actually a Cummins heavy truck engine. With proper maintenance, it should last about 250,000 miles. The injectors will need replacing every 100,000 miles. I would say 500,000 is average for the engine. I do not agree about the injectors. The truck will wear out before the engine does.