Fan is running always on at full speed

Hi, i have a late 2011 macbook pro. Few months ago, video card stopped working (i know this model has a thermal problem) So i took it to the service and they replaced the video card. So the macbook started working again, but it was very slow and crashed after a few minutes. So they also replaced the processor. Now the macbook runs perfect, but the fan is always on at full speed (at 6800 rpm!!), since the moment you press the power button. It won´t stop, even if you put the machine to sleep.

I tried:

-resetting SMC

-resetting PRAM

-Programs like TG pro to control fan´s RPM but they do nothing.

None of them worked. All the temperatures in TG pro seems to be normal.

-CPU work is around 2%, it has been formatted recently, so it has no programs installed at all. So there´s nothing stressing the CPU

I ran the Apple Hardware Test, and showed this “4MOT/ 4/ 40000002: Left Side- 7107”

What can I do?

thanks to everyone