As stated above.....the PCM needs to be functioning correctly for the key to work the relay. The PCM controls it.
If you unplugged the different sensors and still the bus is down.....First thing is to check the power and grounds to the PCM.
Parasitic draw and now the bus is down.....you eliminated sensors but the module itself may be the culprit or the bus pair itself may have a problem.
I have the wiring diagrams and flow charts for this vehicle. Let me know what you want to see.