VCDS: CAN Bus Not Ready - Troubleshooting

Hello everyone.

I updated my VCDS to version 21.3.0 today because I wanted to run a scan to check for any error codes.

Interface detected.
CAN: Not ready.

Can someone help me figure out what's causing this?

I last read data using version 18.7 (I think), and it worked fine with various vehicles.

Today, I received an error message on my A4 B5, which has always worked perfectly before.

"While the system runs through the car scan, no control unit data is displayed, and when attempting to access a control unit, such as the engine control unit, the message 'Control unit not recognized' appears."

Thank you for your help.

Hi,

Could you please show me the Autoscan? Has anything been modified on the car in the meantime? Are the pins in the diagnostic connector still in place?

Best regards, Rainer.

Hello Rainer,

It's resolved itself. I tried it again later, and then it worked...