Yes you can put resistor, evidently there is something wrong in motor itself. Very rarely there has been wiring problem,

 

This works even in om648? I have only seen/read about om642 V6 engine resistor trick

 

I've mechanically removed mine when I did oil cooler seals. But before that was running using the 4 ohm resistor

 

Yes. (I'd only read about it working for om648s; seems the universe has now averaged things out )