I never thought of that. So, the system must run open-loop all the time, using fuel maps that only correspond to to engine temperature and load, just like The Olden Days, before lambda fuel control.
The DME does not look for O2 sensor inputs.
Ed in San Jose '97 540i 6 speed aspensilber over aubergine leather. Build date 3/97. Golden Gate Chapter BMW CCA Nr 62319.