vag com wont communicate with van (t4 2.5tdi 02 888 special) checked voltage at obd socket pin 16 = 12v pin 4 = earth pin 5 = earth pin 7 = 12v? traced wire back to ecu still 12v no connection to radio harness, ecu still giving 12v with wire disconnected? does this mean my ecu is knackered...