Hello,
I have a 1995 E320 (W124, M104).

I am getting Code 12 on the car which points to o2 sensor heater and tested the heater ok. I do not see any power from car to the connector where the oxygen sensor plugs in. I ran a continuity test from the ECM to the sensor and it is fine and there is no short either. I checked for power both with engine off and with engine on.

Does ECM cut out power if sensor is not plugged in? Any other thoughts?

Thanks