I have been reading almost all the posts on OVP,O2sensor,EHA
but i have not yet figured out my problem.
My values:
duty-cycle on pin 3, 35% when engine is hot,28% if i push the plate.
02sensor measured output voltage 0.9v when green wire shorted.
O2sensor heater current only 0,45Amps.
3.6 volts on pin 3 whith engine off ingition on.
The coolant sensors have only 5 ohm difference.(compared to each other.)
I have checked the fuses on the OVP - OK!
OVP was labeled SIEMENS (dual fuses)

Problem:
EHA current 0 amps ,not even a microamp.

Pelle ,300E 4M -89

If there wasn't any current flow to EHA you wouldn't have any duty cycle reading. BEFORE checking current flow to EHA the connection to EHA must be complete & the meter turned on to ma, then turn ignition key on to read the current flow!

I have solved the problem.
It was the OVP.

This is how i solved it.
I measured the EHA and i got a value of 20 ohms which looked okay to me ,It´s a coil so it is not the perfect measurement but since i measured from the ecu connector i also had the cables checked.
I dismounted the ECU and the OVP and i was going to open up the ECU but i had forgotten the proper tools.(torx)
I the had a closer look at the OVP and since i am very good at electronics i disassembled it and found out that it had a lot of bad soldering points.
I re-soldered the whole unit and put it back on place.
That's it.
I got another bonus as well ,my A/C started to work.
I would strongly suggest people who have got a car which have a few years to replace the OVP.
The soldering inside the OVP was awfully.

Pelle 300E 4M -89