Mk6 engine management light

[Lloydy90]

Just purchased a 2008 2.2 swb transit.
Just been away camping in it and the misses left the 12v cooler plugged in and drained the battery.
Jumped start the van no problems (didn't realise the 3rd rule. Luckily everything went fine) but today after starting be van up the engine management light has come on and stayed on. Driven 50 odd miles and still on. The van was hunting/ small revs until it was warm (10 mins) van runs fine btw

Just wondering if anyone has any idea before going back to the garage I brought it from.

[Punto443]

If the lights on. It's hot a fault code stored, always better just to plug it in to the diagnostics and find out what it is, saves the guess work Usually faults are egr valve related.