I own a 2003 Fiat Ducato based motorhome with a 2.3JTD engine (not the new style). A couple of months ago the engine battery failed and the van needed the AA to jump start it. On the next trip away the Engine Emission Control Warning light would come on when the engine is under heavy load (ie trying to maintain speed when going up a steep hill). At the same time there was no increase in power. By reducing revs the warning light would go out. This has occurred in 3 rd , 4 th and 5 th gear. 2 garages (one being Fiat) have looked for a cause, checked the turbo, cleaned sensors but the problem still persists. Advice found on the internet suggests the EGR – but Fiat say may engine doesn’t have an EGR. I would be grateful for any advice as the ‘experts’ are flummoxed.