Hello everyone.
I'm trying to deal with annoying problem for which I can't see bright light in the end of the tunnel.
I've recently changed o2 sensor, the problem is, p0141 comes straight up after ignition. BUT! It doesn't when car engine is hot and the problem is with voltage not coming to lambda heater. After digging in the net I found, that o2 sensor has a fuse and I found it in passenger side fuse box with name LAF heater. BUT! Again that annoying butt, there was no fuse...and the worst part is, that the socket is very deep inside(basically showing, that it's not being used) like any other fuse-less socket, while if I take out a fuse next to it, the socket is visibly close.

Some tests done:
Took out sensor and turned on engine, lambda wasn't heating up, tried to connect heater element straight to battery, lambda did become hot. Then I checked voltage of lambda socket on running engine and it was 6-8 v and was gone to zero after 5 seconds after ignition.
Conclusion:
Lambda sensor - 100% working
Heater voltage unstable and stops after 5 seconds. I'm planning to pass 12 volts from ignition. I don't know if it's wise to put constant 12 volts on lambda heater, so I would really REALLY appreciate any better idea.

To sum things up:
Cold car = MIL - p0141
Hot car = MIL - OK
LAF heater fuse(20A) - not present
LAF heater socket - buried deep inside

O2 sensor is new unused before. Any help appreciated, thank you in advance.