Trouble code 120408

Normally this code does not set by itself so do you have any other codes?

If not, then what this is telling you is that the boost pressure is not being controlled as expected. So, it is either not reaching the proper pressure or it is not being vented and it is staying too high.

https://www.2carpros.com/articles/how-turbo-chargers-work

So normally it sets another code that tells you if it is too high or low and that would give us the direction to go.

However, the most likely cause of these issues is an issue with the wastegate that is not holding or releasing the pressure properly.

The way to confirm what this is would be to use a scan tool and monitor the boost pressure command and actual PSI. Basically, this will tell us if there is a leak not allowing us to build the pressure which would mean the wastegate is most likely stuck open. Or the pressure is too high where the wastegate is stuck closed and not bleeding off the pressure when it gets too high.

You could just replace it, but we need to make sure the rod that opens the wastegate is not bent as well.

Please let us know if there are other codes and we can go from there or let us know how you make out.

Thanks

This U code is a loss of communication code, but I would focus on the other codes first.

However, we are going to have to get a new post started simply because they are different than what is listed in the topic line. Others will not find the solution to these issues under this post. So, we need to just keep each post to one topic.

The fact that these codes will not clear is the reason the light will not turn off but let's get a new post started and we will get on this to figure out what is happening.

Thanks