Iveco Trakker -EDC – light continue to burn off at ignition???

Hello, We have an Iveco Trakker ,Vierachser,bj 2001 with 420 hp.For some time the EDC light is lit up during the ride and sometimes goes out again.Sometimes there was also a short emergency run.After that again for a few days everythingTop. Now lights up once EDC and ABS. But the vehicle runs quite normal.So no emergency run or reduced power. But now comes: If you turn off the vehicle, so SChlüssel also pulls off, the EDC warning lamp just lights up! can be done? Zündanlassschalter maybe? I hope you can help me with the problem.Mfg