[The CaT]

Hi.

I need to retrofit only the rear camera. First I tried with a TRSVC adding 5DL to VO, but only the rear camera is connected. But the car can´t communicate with the ecu.

At a second attempt, I tried wiring an ICAM, only adding the 3AG to VO. But I have the same result.
With the car coded, in PDC screen appears the options for the camera, but I haven´t image, only shows the car and distances.

I'm going crazy with this car

What CAN-bus did you connect the ECU to?
p/n of ICAM?
Did you calculate the SVT just for 3AG alone? When doing this, there are two things you need to pay attention to:
HW state of ICAM
HW state of FEM

I connected TRSVC and ICAM to K-can.
The car had not wiring in K-can from factory, but before connecting the cables they have voltage. 

FEM is 61358781423 HW D9.0
Now i don't have the icam here to check.

I'd rather checked the K-CAN once again, since the P/N you mentioned is not compatible with rear or surround view cameras.
The easiest way to do that is to calculate SVT using 3AG in FA, and check the HWEL/HWAP of FEM