I doubt your exhaust leak caused the engine light. The engine light is tied to numerous components from engine, drivetrain, emissions, etc. I have a hand held scanner that has come in handy many times, but I recommend getting a ScanGauge. It gives you a lot of information...too much actually. I just use it to see how I'm doing on MPGs, but if I ever get an engine light while on the road I can tell the severity of the problem.
Please post what you find. It will be interesting to know what code it gives you...or what the dealer says.
2014 Georgetown 351DS
-TruCenter -Front/Rear CHF -Hellwig Links -Tiger Trak -Ran McNally GPS -ScanGauge -Truck Systems TPMS -5 Star Tune