version is 1993 LS400 ECU? Or could someone recommend a scanner for ECU I could use to find out what O2 sensor has gone bad? Also doe anyone know if it is possible to tell which brake sensor complains is "Pad worn" light is on (all pads inspected and all seem to be in perfect shape)

 

1993 should be OBD I. If you want to read the ECU codes, jump T & E1 and read the flashing signals from the engine light. Look for many previous threads that discuss how to read ECU codes.