By - slow-rider94
Already asked in the mb subreddit, picture is only for attention.
I have a problem with my GTR.
When I drive full load on the highway, the power is sporadically throttled to below 400ps. Sometimes the power is there, sometimes it is gone. Check engine light never turned on.
For 4 years Mercedes has not managed to fix the error.
Is by chance here someone who knows the problem?
No warranty in those 4 years?
No one plugged it in to an OBD?
Checked the OBD again and this might be a gamechanger. P1404, P13C2, P0219, U0412
Those are exhaust errors, one of them is an over-rev error.
That over-rev error is what sounds like could be causing this limp mode that engages. Just don’t get why Mercedes doesn’t fix all those codes, that’d be the first thing I do. And then see if the problem still continues.
that or OP is banging off the rev limiter constantly..........
My guess. OPs car was clearly in warranty at some time in those 4 years as car is less than 7 years old. He’s stuck a cheap aftermarket exhaust on it and is pissed that merc have washed their hands of it.
Do any of those exhaust errors involve the valves that open up in sport mode? Afaik those are a very common point of failure which Mercedes never bothered to fix (and are in a constant shortage of for some reason), and they cause a number of power delivery issues which, again, I cannot find a reason for (why would an exhaust flap have any bearing on how the car delivers power? It's just a flap that opens and closes).
if your exhaust is restrictive, like when the flap is closed, gases flow back in due to back pressure. This leads to reduced oxygen and decreases horsepower quite a bit
Faulty wastegates can do the same thing.
I thought the same on my car until I looked down there myself and saw the flaps were stuck open, not closed. Turns out the flaps are usually stuck in that orientation on most cars with this issue.
Then it’s probably cutting power because it’s throwing a code and the only thing programmed if there’s an exhaust code is “CUT POWAAAA”
Sounds about right.
Gonna need more info than that mate. When/how/more description
When I go on the Highway and want to accelerate (mostly from around 200 to 300+), the power is limited sometimes. You can also see it on the powermeter display. Usually after driving 5-10 min fast. If I restart the car, the problem is either still there or will reappear after some minutes. Then the next day, everything is fine and no fault happens. It’s more prevalent after using sport + or race mode. It’s a2017 GTR with 20k km.
AMG tried to fix it by updating software and by greasing the exhaust valves, since that seems to be a typical problem.
Exhaust needs to be replaced or bypassed completely. Had/having the same issues with a 2017 C63S AMG.
The computer person in me says this is clearly an overheating issue. The car person in me doesn't know how car computers regulate things in newer sports cars enough to know if that's absurd.
My gut was whispering heat soak in my ear imaging hard acceleration while already going “200-300+”
And I'm here thinking "user states overheating issue during extended max load. User states restarting computer has no effect"
The car is made for the Nordschleife, so it should be able to cope with that :D
Computer guy in me is *screaming* now
Oil was around 95 Celsius when it happened last time
If the IAT’s are significantly higher it could certainly make a good power difference regardless of oil and coolant temperature
Sounds like it can never be fixed.. alas, I will be willing to take it off your hands. My cross to bear.
MB World is a good resource if you haven’t checked them out. I myself have AMG GTS and have some issues with the exhaust. Do you hear/feel a difference with the exhaust open/close? Owners have shared that with the performance exhaust, one or both of the flaps get stuck and do not open fully, thus the car not being able to get all its power.
I experienced something similar and needed to get a brand new exhaust as you are not able to fix the sticking flap because it is all one piece
its not stuck closed it is actually stuck open in my experience... both can happen and both is bad... fact is: i would start looking for the problem in the exhaust system because this is what the ond reads... maybe its a cat issue i dont know man
worst thing about this ia mercedes failing to service its customer wth
*what the OBD reads
Engineer here , you might have wastegate and or exhaust issues. I’d replace the whole set with a straight pipe .
And i would ask them to check if you have a faulty cyclinder.
It’s still under warranty but they don’t know how to fix it. Even brought it to brabus several times, they’re in my city.
So your really expensive AMG car is under warranty, and they won’t fix it ?
I think you’re too nice with them.
Go to the dealership again, and again. Go a Saturday when they have a lot of people, and start talking more… direct and louder to them. They hate it when clients are not happy, and when clients starts to talk loud about issues, with the dealership full of clients/potential clients.
The car has an issue. With a simple OBD reader, you found the codes.
Now the dealer needs to find the cause and resolve it
Apparently, codes are related to the exhaust.
Maybe an exhaust leak somewhere ?
You need to talk to an AMG-trainer technician.
Have him look at your car. They know how to fix them.
If not, ask for a flying tech from Affalterbach.
If they can’t do anything, write to MB Executives, or even AMG directly.
It’s the best manner to obtain something
I personally have non-expensive cars (35k€ max) but every single issue HAS to be resolved. No matter how the car costs, it needs to works perfectly.
You pay for something, it needs to work.
I would go crazy if my dream car (yes, an AMG is a dream for me) wouldn’t work as expected.
EDIT: just found that : [https://www.mercedes-amg.com/en/footer/provider.html](https://www.mercedes-amg.com/en/footer/provider.html)
It’s the complete adress, e-mail and phone number of Affalterbach.
Mail them, write a letter to them, or even call them.
You won’t lose anything. At worst, they will tell you to go to the dealer. Then ask for more help for them. Don’t drop anything.
Explain them everything.
Your car will get fixed.
If you involve the factory themselves, they won’t have any other choice than fixing it
99% of the dealers don’t give a fuck and would call the police on you if you made a scene
r0b1n68, I have been trying to reach you about your car's extended warranty
😂 cant believe u dealt with that for four years with warranty and mercedes even acknowledged it, I wouldve got a new engine put in under warranty a while ago. Btw out of warranty that engine is over 70 grand
I'd contact legitstreetcars. He's a former MB tech and YouTuber and this is the type of content be would go for.
100% Alex would solve this. He would probably love to make an episode or two on it too, win win.
Is the car modded in any way?
No just stock
Hey, maybe try to connect an obd reader while driving and monitor the intake temps consistently. I have a feeling that the high load is heating up your intakes too quickly thus reducing power. My 06 350z has a very prominent heat soak issue, specifically due to my intake being a short ram style. Track 350z tend to push this intake allllll the way to the front next to the radiator to get fresh air. Your GT-R is crazy, but at the end of the day an engine is an engine and warmer temps will exponentially heat up your engine, especially at the top end pushing 200-300. But anyways gets those codes fixed, maybe route your intakes another way to suit your high speed driving and see if it makes a difference.
Thank you all so much for your help and ideas. Made a new appointment at the dealership for 19.5, will let you know about the progress!
You are sure that there isn't any mods like cete active sound module or any other mods that controls exhaust flaps?
Dear OP, I believe you have a problem with the car but also the air resistance goes with the fourth power of the speed, hence when you are at speeds greater than say 200km/h the smallest additional wind coming towards you will create a big drag that might feel like a loss of power. Can you confirm the stability of the wind conditions? Just an idea!
This is physics but you’re not taking in to account the cars been designed to break the laws of physics. MB AMG dept has been doing it for a while as have other sports car manufacturers. Basically the cars not shaped like a brick and stuff. Tell your physics teacher he’s an idiot and that he should test drive a GTR
Bruh no car can break the laws of physics. Doesn't matter what shape the car is.
AMG GTR can and will
Nah. Mercedes employs physicists and engineers, not magicians.
You seem like a fun guy
I think a fun guy can make a more original comment than that.
This is the biggest load of crap I’ve seen today
I was apparently wrong! I remembered something with four but it is quadratic!
As mentioned, the drag equation with a constant drag coefficient gives the force experienced by an object moving through a fluid at relatively large velocity (i.e. high Reynolds number, Re > ~1000). This is also called quadratic drag. The equation is attributed to Lord Rayleigh, who originally used L2 in place of A (L being some length).
F_D\, =\, \tfrac12\, \rho\, v^2\, C_d\, A,
Can't you get a tuner or somebody to read of your car while you drive it? Some codes might only show up there and then. How's the Temps on exausthmanifold and pressure? How is your cathalyc converters looking? I had a plugged cat on my old e43 and it behaved just like this.
Do you have an aftermarket exhaust? Why isn't your EGR code being fixed, that and your exhaust flap code are your low power issue 100%
Work at a euro shop, own a m177 car, dm me if you want to chat further
Has got to do with the OBD system
Do you have the lemon law in your country / state?
This car is a lemon but we don’t have the law in Germany 😁