5 lights on (track off, vsc track, abs, brake, check light)

speedomoter/odometer out............diagnostic under dash indicated speedo sensor..........checked contacts and swapped that out..........did not work...........pressure checked for leaksin vaccum/emission lines in front as well as running back under spare......track lights went off then came back on.........put on loaner o2 sensor.......
, changed gas cap.........

is there anything else i can check before my worst fear of the module by brake master cylinder is screwed?