[Rajmahal]

Hey I was wondering if anyone had any clue on why I keep getting the CEL for P0299 for my 2015 Mercedes CLA 45 AMG. It goes on and off randomly. I had the Turbo and lines pressure tested by the dealership and they came out okay. I even had the turbo boost control valve replaced. The car would go into limp mode or lose a decent amount of power whenever the light comes on. Anyone got any suggestions on what I should be looking at.

 

[Rajmahal]

Welcome to the CLAForum Rajmahal
Tell us more:
*Did you buy your CLA as a MB Certified Pre Owned from an MB dealer?
*How long have you had it?
*What are the other codes you found?
*What city are you near?
*Your mileage?

:
I bought the car new in january 2016 with 32 miles on it. Ive had it since then. I daily drive the heck out of it so it has around 126,000 miles on it right now.
I mainly get the P0299 code but occasionally a p0102 code would appear. I reset the code via a bluetooth obd reader but it appears every other day or so.
The car currently has a weistec mid and down pipe, air intake,blow off valve and tune. I had the systen pressure tested but the mb dealership found no leaks. They replaced one part but the problem still occurs. Ill post extactly what they wrote when i find the service paper.

 

[Rajmahal]

Heres what the dealership wrote and found during their inspection.
The problem still persists even after.
The code will randonly appear and then i would clear it and would appear again after a few days or hours.

"

Verified check engine light is on. Connected SDS and performed quick test. Found code p029921 The boost pressure of turbo charger 1 is too low the signal amplitude is less than the minimum amplitude processed code. Removed intake housing and smoked intake system and check for leak. No leaks found. Checked turbo and found good. Checked actuation at turbo diaphram and found performing as designed. Pulled vacuum at turbo diaphram and found hold vacuum. Checked duty cycle for boost pressure positioner and found it is below spec.
Recommend to replace.
Removed and replaced boost pressure positioner. Connected sds and cleared fault codes.test drove vehicle. Ok

Part number 00-153-18-00 pressure trans "

 

[Rajmahal]

It appears randomly. Sometimes under acceleration or just at constant speed. Whenever i reset the cel it usually takes anywhere from 5 or 8 hours to a 2 or 3 days for it to appear again. I feel a loss of power either to something mechanical or the car goes into limp mode whenever the cel is on. And i currently have no way monitor the boost pressure.

 

[Rajmahal]

Ill check out all the hoses.

 

[Rajmahal]

Seems to me to be the actuator. The car is inconsistent with boost pressure. Some days im getting full boost some days only 5 or 6 psi woth no cel at times.
Just ordered the actuator so ill keep yall updated.

 

[Rajmahal]

Just replaced the actuator light still came on.
Pressure drops to around 4 or 5 psi.

 

[Rajmahal]

Took a look at some of the wiring coming off one of the boost sensors.
Pretty burned on the shielding.
Maybe thats tripping the CEL?

 

[Rajmahal]

 

[Rajmahal]

Already went to the dealer multiple times. They just replacing anything at this point.

 

[Rajmahal]

Yeah at this point just checking everything. Alreasy wasted a few thousand at the dealership for them to try to figure out whats wrong but they just keep suggesting to replace different parts each time.
Pretty sure they pressure and leak tested when the car was cold. One of the cracks if any probably expands and opens when the car heats up.

 

[Rajmahal]

So not the actuator, have you checked all your electrical connections and to the boost sensor? It sounds like it may be electrical. What remap or tune are you running?

They replaced the primary boost sensor listed above in the first post. But not too sure on what other sensor or electrical component it could be.

 

[Rajmahal]

Also the problem happened well before any of the aftermarket parts

 

[Rajmahal]

I havent noticed any unusual smoke.
Last thing that could be the issue is the connecting point for the actuator. Attaching a photo as an example on where. Theres a little play and its not sitting quite right where it should be. Thr actuator still looks like ots opens and closes tho.

 

[Rajmahal]

Nope looks just like yours. Just eliminating things now to check.
So i noticed when i just drove. I got full boost but around a few seconds into the acceleration it dropped to around 5-6 psi.
When it did give me the full boost it was around 22.1 psi.

Still thinking its one of the hoses but still conflicting since the dealership did conduct a pressure and smoke leak test. And it passed. They even said the turbo was in good condition.

 

[Rajmahal]

There’s a bit of play. Your pic looks normal. Here’s a pic of mine to compare the adjustment. The arm isn’t rubbing on the turbo housing right?
View attachment 67990

Also does the end of your actuator rest on that lip where the nuts are located?
Mine moves past that lip and does not rest on it.

 

[Rajmahal]

Would a loose wastegate flapper be the cause?
The area where the actuator connects to the turbo seems to have alot of play. Moves beyond stop point ( little lip on turbo)

 

[Rajmahal]

Shoot. At this point running out of options.

 

[Rajmahal]

just following up. I think this is your boost issue. There shouldn’t be any play in the shaft where the wastegate connects to. I think the play is allowing the valve to slightly open.

Yeah i figured. Gonna remove the turbo tomorrow.

 

[Rajmahal]

This incredibly small tear was a huge headache for my car. It would cause an intermittent cel with temp fluctuations. Never rule something like this out. This is the pcv going back to the mani btw.

Sent from my SM-N986U using Tapatalk

Will do thank you.
Taking everythibg apart tomorrow. Gonna do a deep cleaning of the sensors and hoses. And checking each hose. If not gonna do a turbo replacement since i dont wanna mess with replacing the actuator arm. Might as well repalce the entire unit if i dont find anything. Ill keep yall posted.