Volvo V70 II automatic transmission

Hello, errors come every now and then. It sounds as if the gearbox is switched off, then error engine maintenance, emission maintenance and then “brake motor off”. Revometer goes to 0 and speedometer to 0. I stop motor off and after a few minutes I start and it runs round again. I get out of the battery and wait 10 minutes. The errors are gone. After 3 weeks or 2 days the error comes back. Was already in the Volvo workshop and have the errors a communication between ABS control unit and engine control unit faulty. But what does this have to do with the transmission ? Does one have an explanation ? Greeting Rupert