Sm 52-2 ewk error

hi, there is a problem with the press sm 52-2 of 2003 year. swears at the ewk1 and ewk2 boards, having measured the input power supply there is an additive on the + - 15 vdc line. (Down to 5 vdc) Of symptoms 9 - the main compressor does not start stably, (it can work for no more than 3 seconds, the pressure does not gain), in general, the car is standing, when trying to start it, it does not react to anything. It is very expensive to change the payment if there thoughts, thanks in advance. DYN error codes test ewk1-fffb ewk2-fffb. sorry for google translit