Yesterday in the workshop!!!!

Hello people! First of all thanks to all who deal with my problem or much more with the problem “VOLVO S60 ABS control unit”! In itself such a part (hydraulic block+control unit+motor) is not repaired, but only replaced, because it is supposedly a safety-relevant part! But now it is so that there are companies that accept this problem and check such ECUs. In my specific case (I reported a long time ago) The expert in the workshop then said it would be due to the carbon brushes that are in this engine (which is sitting on the hydraulic unit). Only again he started to screw this engine off from the hydraulic unit yesterday, and when it was removed, he said. ” Well, the carbon brushes don’t look bad and the collector seems to be fine too. The next step looks like this, that he cleans the part with compressed air, reassembles it, sprays the plugs with contact spray. “You’ll see, now it works” means then the mechanic!!! “Why should it work now” I ask on it “nothing has been repaired!!” “Now don’t be so pessimistic” his answer to it. Well then – all assembled again – attached to the test device, all error codes deleted, and then test drive – and see, it works!!!! All this was yesterday, we come now to today!!! Departure in the morning, no problem. But after 20km display board computer “slip protection – maintenance required” and “brake assistant – maintenance required” That I now curse my car (as well as the mechanics working on this part) gets itself!! In addition, it is clear that up to now about 500 € have been plugged in and you are currently as far as at the beginning!! PS: Can it be that my car has “multiple sclerosis”? That would explain a lot, since d I want to say that it all works right now (ABS+DSTC) and it comes back to the problem described above while driving!!! A frustrated Volvo driver who only returns to this car again!!