01 s40 crank no start

[1965Olds]

Have intermittent problem with no start. no fuel pressure no injector pulse. Bypass main relay and fuel pump comes on but no start. Also can not communicate with ECM. All other modules okay. Had ecm 11 code for ect sensor but that showed up in DIM module but won't clear. Car has been sitting for some time and sunroof drains were plugged and keep getting standing water on passenger floor. Cleared drains and now floor stays dry. No check engine light come on either, Also has the x symbol over a car and shift light keeps flashing. Problem has been intermittent as I have been doing brakes front and rear. Now problem is constant. Any advice?