[BrianTruelove]

Bump - Updated original post with new diagnostic information.

Preparation for diagnosing:

The Solenoid Valve Diagram

Quote:
" BPV solenoid. It is a pulse width modulated (PWM) valve with one outlet and two inlets. The outlet goes to the BPV, one inlet goes to a manifold source and the other
goes to the vacuum chamber. The ECM uses this to manipulate the BPV. "

Quote:
" This is a 3 port solenoid with one port connected to the intake manifold, one port connected to the bypass valve, and one port connected to a vacuum chamber located
on the bottom of the intake runners. This chamber is fed a vacuum signal through a one-way valve also known as a check valve. "

1) Replacing the bypass valve solenoid under the intake manifold.
Location

Removal consists of taking off the metal clip to the electrical connector. Pushing in all 3 plastic prongs on the underside of the solenoid simultaneously while pulling the solenoid down. Tricky but doable in less than 5 minutes. Installation in the reverse order.

2) Attempting to bypass the bypass valve to see if the turbo hits 20 PSI. Temporary, not a long-term fix.
Bypass the Bypass Valve
Bypass the Bypass Valve (2)

Quote:
" The ECM can no longer open the BPV to reign in trq production.
When you put the pedal to the proverbial metal, you don't have to worry about some or all of your boost pressure being released because of conservative "torque
management" protocols GM put in place.
The BPV gets 100% of the boost signal needed to ensure the valve stays shut. "

Quote - What is needed:
" 5/32" hose splice
5/32" vac. cap
3"-4" of 1/8" or 5/32" vac. hose "

2A) Vacuum testing the intake manifold vacuum chamber. (If the system hits 20 PSI and operates normally with the BPV closed via the test above)

Using a vacuum gauge to ensure the vacuum chamber connected to the intake manifold holds a vacuum.
Verifying the check valve is still one-way.
Using a vacuum gauge to ensure that vacuum is being created in the lines going to the solenoid.

3) Wastegate Actuator

Using compressed air I am going to ensure that the wastegate opens around 20 - 40 PSI.
Video Tutorial


Edit: Replacing the bypass solenoid did not work. Bypassing the bypass gave little not no extra boost, but in the process I discovered I was getting ~8-9 PSI which is close to stock I believe. So I don't think the turbos bad, certainly doesn't feel like it. Wastegate actuator is working fine.

A quick favor?

Can anyone tell me the voltage of their wastegate solenoid with the key on not running. Mine was roughly 8.1 - 8.6. Perhaps it is an electrical issue.

Mechanically everything is sound. Maybe the PCM is bad?

 

[BrianTruelove]

Where I’m at right now is I got a BNR recirculating bypass valve on the way. I hit the stock bypass with a vacuum gauge and got no vacuum whatsoever, I think the diaphragm is torn.

Edit; No clue why my phone created a second account to post that reply I thought I was signed in. 🧐

 

[BrianTruelove]

To confirm, this code was absolutely being set by a torn diaphragm inside of the OEM bypass valve. BNR sells a nice recirculating valve that is plug and play with no codes being set - no tune required.

Hope this helps anyone before they see what I saw, every post said to replace the turbo. Nonsense. 3 T30 screws is all that it takes to swap, good videos on YouTube.