my wife her audio a2 1.4 petrol bj. 2002 has been having a problem for 1 week. it lights up the abs symbol and the yellow triangle with the circle around it! error memory says: brake electronics builtil esp 1 error found 00668 onboard voltage clamp 30 16-00 signal outside of tolerance. how do I get there now the error on the loop? battery has in rest mode over night 12,25v. with running engine 14,2v sheet protection on the plus pole is ok and also the battery contacts are not corroded. s teacker on the ABS block is also nix corroded