I did a live readout with HFM-scan in my 1993 500E.
When the engine is idling or Iím driving and depress the accelerator, the
50% O2S 1 (before TWC) (G3/2) not operational or defective, open circuit
The O2-sensor was swapped one year ago with an OEM part.
Why does this only appear when the engine is idling?
Is the sensor really faulty?