O2 sensor simulator on X5 4.4

[partam]

Hi all

i have a 4.4 2000 X5 and bought an O2 simulator online as i removed the cats from the car.

After many trials i couldn't get the MIL off and i had a slow response error.

I managed to get the simulator to run faster (simple electronics 555 timer) but also i had different errors.

This simulator runs by cutting the rear O2 signal wire and put the simulator output on it.

Does anyone know if i can do this because all other BMWs succeeded to bypass the O2 sensor.

Also where i can find the logic documentation for the X5 ECU? Like when the MIL goes on and for what value or voltage?

Thanks

[partam]

Guess no-one ever removes the cat.

In my part of the world it's not required so when we have to exchange after some 100k it's better to remove but need help with OBD2