EDC16C34 FRP problem

[g5n14]

Hello guys!
Have one very interesting car arrived to my shop.
Peugeoet 207 90hp 1.6HDi
Stoped starting, came by towing truck.
Makes strange noises (buzzer type) from Fuel Pressure Regulator which is on high pressure pump.

Errors in ECU - P0658, which is 5v sensor circuit voltage too low.


Checked everything:
Replaced fuel pressure regulator
Checked all the common wiring problem places, all looks good.
Changed ECU
Changed BSI
Disconnected all the components one by one, only while disconnecting the accelerator pedal p0658 is being replaced with some accelerator pedal signal too low.


Fuel Pressure Regulator is supplied after ignition is set to pos.2 with 12V from BSI, and being controlled from ECU by supplying PWM ground through some SOP-8 element, forgot the name already. When I measure signal coming from ECU (ground probe to FRP pin of ECU, V probe to + I get 8 volts while buzzing is present and 6 while trying to start, while should be approx 11-12). As a result 0 fuel comes to injectors. As soon as I supply manually good ground to ground pin of FRP everything is back to normal and fuel is supplied to injectors.


Once again, 2 different ECUs, same problem, so not the ECU 99%, what might be the problem? Once again, disconnected one by one each and every element and buzzing Is present all the time.

P.s. both ecus immo off by PSA EDC16 soft just to make sure.

Thanks to all who are trying to help!