I have a CLA 200. 1.6L M270 engine from 2013.
Don't know if this is the correct place but i'll try here.
About a month ago my car went more and more into limp mode, and I figured it probably needs some service. By the time I am writing this it has not been looked at by a technician.
So I called them and they stated they would charge 179 euro pr hour before tax just to look at it. Thought that was too much money so the last 6 days I have tried troubleshooting the problem myself.
Hooked up and ODB scanner and got an errorcode P029921 while the car was in limp mode.
"The boost pressure of turbocharger 1 is too low. The signal amplitude is less than the minimum amplitude".
So a little troubleshooting. I can recreate the error. It usually happens at 80+ km/h/50+ mph, at low revs, 7. gear, constant speed, uphill.
I took a picture of the turbo graph as it happend.
View attachment 67280
Can't say I have encountered the same problem at higher revs. So the last couple of days I have been using sport mode more often to see if that will induce limp mode, which it hasnt. And the car seems perfectly fine. No errors on the dash either when it's in limp mode.
If anyone has any idea of what it could be, any thoughts would be appreciated.
Reason why I am making a forum post inititally is because I just learned the price for a new turbo and I don't want the shop to have the car in for longer than necessary.
Thank you in advance