Check engine light on and code120308

Tiny
CHRIS THOMAS2
  • MEMBER
  • 2012 BMW 528
  • TURBO
  • AUTOMATIC
  • 186,000 MILES
I don’t know what’s wrong with my car. I don’t have a check engine light on it though after I get the drivetrain malfunction.
Wednesday, June 29th, 2022 AT 7:05 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
The code #120308 boost pressure control, plausibility: pressure too low, I would start by checking the turbo tubes and boots to make sure they are in good shape with no leaks. If okay I would check the turbo main shaft endplay, if excessive I would replace the turbo. Here is a guide to help you see what I am talking about. Also, I have left instructions on how to change out the turbo in the diagrams below.

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

Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.
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Thursday, June 30th, 2022 AT 8:44 PM

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