P38A rear wheels always locked

When I turn on ignition, rear wheels get locked and there is always hydraulic preassure. I realized that selonaids in abs booster unit doesn't work properly. I checked booster socket (C0501) and can't get any signal. I opened the abs ecu case, at first sight Abs ecu looks fine. I had a short circuit at wires of the booster selonaid, which I fixed it before. But now I can't get any signals. (No errors on diagnostic) Does anyone had this problem before? Any suggestions to look for? Thanks..