LEAK DETECTION SYSTEM

The invention relates to a leak detection system on board of a vehicle comprising a fuel tank (), a filler pipe (), a venting line () for recirculating fuel vapors from the tank to the filler pipe, said system having a combination pressure and temperature sensor mounted in the vapor dome of the fuel tank, and a pressure sensor located in the recirculation line above the highest possible liquid level that could be present in the recirculation line and to methods to detect said leak.