Hi, I don’t know if I’m being stupid here or whether it’s a common fault but I have gone to plug my friends car into vcds to see which codes the ecu are shooting up. When I have plugged it in the car won’t communicate with the ecm. To make sure it wasn’t his obd port I have plugged an old ecu in and it works fine, is this a common problem? I can’t list any codes because I can’t access the information. I read his car 2 days ago perfectly fine but today it just won’t recognise the ecu and I’m confused. I tried reading the ecu Id with mpps but again it couldn’t Id the ecu so I don’t know, if anyone has came across this problem and found a way to fix it it would be much appreciated