2zz swap engine codes P0135/P0141

[JNikas7]

Hello all,
I trusted a person named Rhys - he might be a mamber here too - STAY AWAY!, and apart from having my car for 4+ weeks to do the swap although I supplied all the parts to him, he managed to destroy 2 gearboxes (one corolla and my original fl MR2)
He also b..ed me saying hundreds of lies, not being honest at all etc about what he has done and what he has messed up with.
Obviously the guy was experimenting on my car.
To the point now.
Apart from other issues I am trying to resolve, I have those two fault codes.
P0135 and P0141
Both sensors are relatively new and were working fine on my 1zz mr2.
I have read that it might be another wiring loom mod error by him.
Anyone could help me try to resolve the issue would be really appreciated as I need to go on a roadtrip soon and I know I shouldn't be putting miles on it while O2 sensors are not reading as engine is running rich.
Kind regards

[jonbill]

Check the resistance and continuity across the two pins on the same coloured wires on the sensor plug.
If you have continuity and around 15 ohms, (I think)  then the problem is in the loom not the sensor. If you don't have continuity and that resistance, then the problem is the sensor.

[shnazzle]

The o2 sensor wiring is one of the things that is done wrong most on the 2zz conversions. Might be worth verifying against the diagrams in the 2zz conversion guide on here. I've just updated it with a diagram from @mulaz