p2456 permanent implausible signal
 

So, I don't know what to do next. I had this issue for the last 3 months, and I've expend almost 2k in trying to fix this issue. I was heading back home when all the sudden check engine light came on and limp mode with it. I check on it, it was the DPF sensor, as other pictures completely melted. I took to the dealer, they changed the sensor, and the check engine light came back on. Again, I took it to the dealer, they replaced the sensor and admitted that they had mixed the sensors... Now I have my car back and check engine light is off. However, when I hook up my OBD scanner, says the same code p2456 permanent implausible signal.

I've reading and trying to see what am I missing. So, any comments on this? This a JETTA TDI 2015 SE