2 weeks back on my way to work (driving at around 60mph) my car started making an awful noise whenever I would push the gas. Stopped accelerating altogether. I managed to coast into work, shut it off, and used my code reader to check for issues. I got the code U0073 for "communication bus a off". After work I started it up to see if I was still stuck with no power. It allowed me to accelerate a bit but the noise was still there. I got it towed to my mechanic who says he was able to find the code P2119 something to do with the throttle body. And he suspected an issue with the turbo based on the noise, but thinks the u0073 code is not really an issue. He doesnt turbo work, but he cleaned the throttle out for me and I drove it home. Noise was mostly gone, but it was still driving with low power. Had it towed to Hertz for diagnostics on turbo and throttle as well as computer code. They said it was ONLY a throttle problem. Replaced throttle. Car still makes a horrid noise when gas is pressed. Will accelerate (got it to 4th gear no issue besides the noise) and the P2119 is gone. But... I still have the U0073 and now a P0101 (something wrong with the maf). The AT light comes on intermittently but will go away with a restart.
I'm assuming I need to replace the turbo(though, the noise does not sound like videos I've watched of a blown turbo, but comes from that general area) but I cant seem to find a connection between all these codes or how to diagnose the U0073 since both shops its been to say there is nothing wrong with the computer. Also it shows a P0012 from time to time, but I've been told this is very common with this make/model. Any ideas?

 

P0012 is serious. This relates to Camshaft Position Timing over-retarded

I would get this looked at ASAP.

Could be low oil pressure = Bad
Timing chain stretched & possibly ready to snap = Bad
Variable valve timing solenoid worn = Bad
Oil Control Valve stuck = Bad