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Discussion Starter · #1 ·
Hello everyone- I’m a newer GLA owner and I’m wondering if anyone can help me with a issuer I recently ran into with my 2015 GLA 250. I recently had my engine light come on and needed to have thermostat housing changed. That gets done and shortly after I’m on the highway and when I went to pass a semi I punched the gas and my check light came back on and I had a lack of power. I could hold the pedal to the floor and it just slowly climbs in speed. I get home and check it see if maybe a sensor or something wasn’t connected, anything leaking, etc. I noticed the air intake tube had a decent size hole in it near the turbo, so I order a new one. In the meantime I taped it up with some metal tape and had the code reset and he says the code is say “low turbo pressure”. It went back to driving like normal, until I was on the highway yesterday, punched it and it’s doing the same thing. Check the intake tube again, tape is fine but the cloth part of the tube is has some gaps. Still waiting on the part but now I’m wondering if it’s more the boost pressure sensor or something else? Anyone experienced this? I tried searching the forum but not finding anything similar. Thanks and sorry for the long post!
 

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The extreme loss of power is the wastegate going full open. It happens to me. Happened once in the line up to get on a track, so THAT was fun driving on track with no turbo!

Anyways, in my case, it was the seal between the intake and the engine, there was a leak there. It would never have been found and still giving me periodic boost leak (for me every 2000-5000 miles there would be a rash of codes and then gone), except I had the thermostat replaced, and it was found during recovery.

Replaced that, GTG since then, car has been rock solid.

My point is just that it could be in multiple spots, but anything that can be seen as a boost leak will throw that code and cut off the wastegate (open). What's really fun is it doesn't ALWAYS open the wastegate. Sometimes it will come on and the car drives fine, and sometimes you get the loss of power. fun!

Happy leak finding!
 

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Discussion Starter · #3 ·
Interesting bc I had the mech replace the intake gasket when he changed out the thermostat housing. I just replaced the intake tube and had the codes reset, seemed to drive fine around town until I got it on the highway and punched and it started acting up again. This should be fun!
 

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Discussion Starter · #4 ·
So the code I had is P0299-21, he’s showing me that when he puts his finger on the vacuum end you can see the actuator arm slowly moves. He’s thinking it’s bad. The issue is find one, it doesn’t seem to be a common part to replace. Anyone else experienced this?
 
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