Looking for some input here because I am getting sick of dealing with the Service Department at Mercedes.
I recently purchased a 2018 GLA 45 from Chicago area. Had it shipped to St. Louis where I live. Car drove perfectly and had not a single issue when it arrived (drove it for about 200 miles).
I took it to the local automotive to get the emissions passed to register vehicle in state of Missouri. It did not pass on a case of "Cat. Conv. Unsupported-Programming Error" which the exhaust is stock an hast cats.
The car only has 19k on it so it being under warranty I took it to Mercedes Service Dept. here in St. Louis. They decided to reflash the ECU.
Once they did it pulled the code P0299 Low Boost. Since then they have replaced the ECU, vacuum pump, purge valve, and now we are waiting for the Crank Case Ventilation hose which is on back order.
I am tired of Mercedes fiddling around with one thing at a time. Does any body have any ideas on what could be happening? The car is completely stock from what I can see. I suspect the car was previosuly tuned but since we took it back to stock I feel their may be a correlation with that. Any thoughts?
I dont know if my boost issues could apply to the issues you are having. I one day decided to cut my muffler, resonators, and went with a catless downpipe/midpipe. I guess all the new pressure running through the exhaust broke my valves at the back of the exhaust which basically caused it to go into a limp mode and not make any boost any more. Maybe try checking those valves and motors attached to the valves that make them accuate.
I dont know if my boost issues could apply to the issues you are having. I one day decided to cut my muffler, resonators, and went with a catless downpipe/midpipe. I guess all the new pressure running through the exhaust broke my valves at the back of the exhaust which basically caused it to go into a limp mode and not make any boost any more. Maybe try checking those valves and motors attached to the valves that make them accuate.
I have not updated my post yet, but your solution was very similar to one I have found. The owner previously to me had a PLM Downpipe installed for about 5-6k miles. Once the stock DP was re-installed and ECU was reflashed problems occurred. I decided to take back the vehicle from the dealership because of the delay in parts they were guessing could be the solution. (Car drove fine, just was not boosting at high levels) After driving the car about 800 miles, limp mode went away and the car now drives fine. I am not sure why but I will take it! lol
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
