My wife drives her car like a grandma so we never noticed that there was an issue, however I took it for a drive and noticed that the car WILL NOT boost over 9psi. Car was road tuned about 2 years ago and has otherwise been unmodified since. I conducted a boost leak test and found that the turbo elbow gasket has a small leak but that part won't be under positive pressure so I am not worried about it for now. I replaced the exhaust manifold and manifold-turbo gasket as well as replaced the air filter and cleaned the MAF.

When driving the car if I try to lean into it the car will throw the P1235 code. I have the boost reference line for the gauge tied into the BOV line. I am running a Cobb 3-port and will go back through the car to make sure that I have them plumbed correctly but I am 99% sure they are right. I haven't messed with them. I did disconnect the reference line from the WG and was unable to boost more either.

I am beginning to think the turbo is shot - Arashi 25G - but the turbo has no noticable shaftplay.

The wastegate arm is connected and has preload sufficient to hold it shut.

Any ideas on what the culprit could be?

 

In case anyone was wondering what the culprit was, my HFC yeeted itself into the muffler and blocked the airflow. I’m assuming that I had a blocked cat when I got the car tuned. The car runs better than it ever has, but I am going over 30 psi and I’m not thrilled about that. I’ll have to get the car tuned again but I sure do love fixing problems for $free.99!