Hi, i am a mechanic and have problems with the ABS. When the engine is started most times the speedometer goes up and down several times and giving a 4WD fault message on the dash. When reading the DTC there is one or more speed sensors in random order faulty. All speedsensors are replaced. The ABS ECU has been send to a company in Germany, they stated that the hardware is good but the software might be the problem. Where i live there is no Porsche or other VAG dealer. My question is, can the unit be exchanged with a unit that has the same number?