Hello,

I've been reading the forums for some time now, and sadly my first post is going to be one of frustration and despair.

Currently my GT-R has been sitting at a dealer in Florida for almost 6 months total, with over 4 months being this particular stay. The full details of the issue and timeline of events are detailed below. At this point I'm at a loss as to what to do, and after 4 months I was asked by the dealer to contact Mercedes CAC. Initially they were responsive, and even sourced a replacement ECU (didn't fix the issue sadly), but they have since stopped responding to me by phone or email.

If anyone has any advice on how best to proceed, I would be eternally grateful. As it stands, I have a $200k paperweight, that was still running when I delivered it to the dealer, yet now is totally inoperable. I am certainly no stranger to exotic and high end cars, and have owned cars from almost every marque, but never have I experienced this.

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I purchased the car in September 2022 and traded in a 2022 Audi R8 (purchased new). Prior to purchasing the AMG GT-R, it had received a replacement lithium ion battery in July or August of 2022. Within 3 weeks of owning the car, and approximately 500 miles, I had my first warning about the battery not charging on the dash, recommending to stop the car. I purchased a lithium ion charger from CTEK and the issue went away for about a week. This issue returned, culminating in multiple warning lights, and stuttering on gearshifts. I took the car to Mercedes *** where the car sat for almost 3 weeks before being diagnosed with a faulty alternator. This was ordered, and about a week later I received the car back, supposedly fixed (1 month total to repair).

Within 2 weeks of receiving the car back, the battery charging errors came back but more severe, with multiple warning lights, loss of ABS, traction control, rear wheel steering, unable to shift gears, and stuttering on acceleration. I limped the car to the dealership (Mercedes ***) on December 1st 2022. The car was diagnosed with a faulty rear SAM within 3 days, and the part was ordered. After 2 weeks the part arrived, and I was told that Mercedes would not allow the repair unless the ECU and battery were also replaced at the same time. After a month of not being able to obtain a new battery, Mercedes now agreed to allow the repair to continue with just the SAM and ECU. Once these new parts were installed, I was told the new parts could not be programmed to the car (early January). A ticket was raised with Mercedes HQ to request advice on how to proceed, but after 2 months of no response, a decision was finally made to order further replacement parts. These parts were unable to be obtained, with no ETA from Mercedes (another month passes). Eventually I was asked to call Mercedes CAC to create a ticket for assistance. A new ECU was miraculously found, and delivered the next day. However, this did not resolve the problem, and we are back at the same issue of being unable to program the new ECU to the car. Another ticket has been created with Mercedes HQ, and they have still not responded. The car in its current state will not start, and has numerous warning lights on the dash.

To the dealership's credit, they have kept the car indoors at least, but I am getting absolutely nowhere with this. I'm stuck with a car I cannot drive, and cannot sell because Mercedes themselves cannot figure out how to resolve the issue, and will not communicate a solution to the dealer.

Thank you,
Dave

 

Ugh, that's so unfortunate, and empathize with your situation.

Recommend researching the Lemon Laws in FL (or your state of residence) and seeking legal counsel.

MB/Dealership needs to make you whole.

This may be a long shot, but ensure that the techs have thoroughly inspected the wiring harnesses in the rear.
There are posts about rear wiring harness fraying due to friction/rubbing on ?body panel, etc and this caused all sorts of electric gremlins.

Best of luck 🙏

 

Can you verify what year this GTR is and whether you bought it new or not? If it is new, then absolutely invoke the lemon laws and have the dealership buy it back from you. I've had a Maserati that had an incurable problem and the dealership gladly bought it back from me. I didn't have to invoke the lemon laws, just the discussion of the lemon laws was all it took. If this is not a new GTR, then you have a whole different set of problems.

 

Unfortunately, the car is a 2018, so no lemon law for me. I did purchase an extended warranty with the car, but that has been absolutely no help since Mercedes seem unable to actually fix the car.

Good shout on the wiring harness, and I did send them the relevant information on this forum back in November, but they state the wiring harness is not the issue.

My main issue here is that there's simply no end in sight. Can Mercedes really hold their hands up and say "we don't know how to fix our own nearly new car"? Mercedes have made the car worse than when I gave it to them, and now they have removed any options I had since the car is no longer able to start/drive since they have attempted these repairs.

 

I suspect ihe bought it used. However he should have a warranty of some sort I would think.

The problem rests with MB AMG Germany. They control the electronic profile of the car. Downloading a ECU should easy step as would be remote diagnostics. There are regional techs that should be contcted through the dealer that may be able to fix it themselves and/or work with Germany to resolve the issue. They have direct contacts in Germany.

I don’t think taking it to another dealer would help. But talking with the dealership GM may get some leverage to get the right people involved.

Best of luck.

 

You're a nicer man than me, I'd be raising hell over this fiasco! I understand diplomacy must ensue but holy $%^&! MB has some *****! I sincerely hope there is a car for you at the end of this horrific tunnel, and some compensation too!

 

Curious to know the mileage and if you are aware of any modifications by previous owner(s).
I have the same year and model so please keep us apprised of this very unfortunate situation.
Best of luck.
​​​​​

 

10,000 miles, no mods, clean car with full PPF put on by the original owner. Was still on the original set of tires too, so highly unlikely it was tracked.

 

Thank you kindly. I only have 4500 miles on mine and I am the fourth owner.

 

You need to have a meeting with the general manager. Don't accept anyone else but the general manager. If it's the dealership where you bought it that should make a difference. Be nice, but effectively the purpose of the meeting is to not leave until you have reached an agreement that you find acceptable. That might be they buy the car back from you but be prepared to take a haircut. I'm sure you bought it "as is" but If you can clearly document that they made the car worse while they had it that gives you some ground for argument. In my opinion by sending you to Mercedes they are trying to relieve themselves of responsibility. I wouldn't accept that and I would hold them responsible. For future reference, whenever I buy a high-end car from a dealer, new or used, I have written on the sales contract that anytime the car is in for service the dealer must provide me with an equal or better quality car until such time that my car is repaired. I have driven some very nice cars because of that and it also creates a very considerable incentive for them to get my car back to me in a timely manner. Good luck!

 

I would find the best local attorney that specializes in Lemon Law types of situations and pay out of pocket for an initial review of the situation. Even though the LL doesn’t apply, MB USA has the responsibility to fix your car especially if the warranty was an extended OEM type. Regardless of the warranty, they still need to be able to repair the vehicle. You need legal assistance from now on, and I hope it can be resolved soon.

BTW: the first thing I thought of was the chaffed wiring loom at the left side, back of the trunk where the First Aid kit resides, as when chaffed and shorting out, a myriad of electronic issues can occur.

 

Brutal and a frustrating read. Sorry you’re experiencing this.
Honestly, this has all the hallmarks of a tech who was in over their head. They sound like they started throwing parts at the problem. Alternator should have been bench tested before replacement. Since the symptoms manifested identically after repair, chances are it was not the issue. Which raises a red flag.
That’s pretty bad.
More red flags

The ECU part of this seems odd. The rear SAM is programmed independently of the ECU. I question their rationale. I suspect they installed the SAM and it may not have solved the problem. (Like the alternator)
While testing batteries is fairly straightforward. If any doubt remains when diagnosing electrical issues, sometimes, it’s just easier to swap a known “good” part. I find it difficult to believe they couldn’t find a known good battery in the local/extended dealer network, especially for diagnostic purposes.
This sounds unacceptable, Who is following up from the dealer side? This is a procedural failure. In the end the car is sitting in the dealers shop and it’s their responsibility to get the car on the road. Even if it means CALLING Germany daily. Waiting for emails is unacceptable.
Where is the old ECU? You should be able to at least start the car…
In theory this is correct. Problem with electrical issues is they are extremely difficult to diagnose remotely. Many times it’s a tedious process of trial and error tracking down complex electrical gremlins. The time difference also adds to delays. Plus, we’re not privy to any internal discussion between the dealer doing the repair and the factory. They may require the dealer to do their due diligence to rule out any potential mis-diagnosis. There may also be some info “lost in translation” between the tech and the service writer. It’s really difficult to get clarity on what’s happening here.

I’m not here to defend MB or the dealer, as I feel the OP has been more than reasonable here.
But these cars ARE complex and constantly redesigned. There are plenty of mechanics that are good “wrenches”. But todays cars require a hybrid skillset of computer tech, and traditional mechanical aptitude. They (tech) will also need enough experience to have the organized, diagnostic workflow discipline required to solve “out of the norm issues on out of the norm cars” such as the OP is experiencing. The automotive repair industry is not immune from the skilled labor shortage and employee turnover plaguing many industries.
Sometimes “what happens in the shop, stays in the shop” 😀
For sure, this is the best course of action at this juncture. Get another set of eyes in there!
At this point the die is cast. The car is now inoperative and bringing it to another tech “on the hook” isn’t even going to be back to square one, since the car is basically apart.
But unfortunately a learning moment for anyone in a similar situation. If you’re going back more than once for a repair or an improperly done repair, best to try another dealer/shop quickly. I can empathize with anyone in a similar situation.
Sometimes it’s just a question of bad habits. Many of these cars sit for extended periods, but they like to be driven. Consequently, the batteries can get rundown. Jumpstarting the car can wreak havoc if someone isn’t paying attention or just plain dumb (especially second hand cars that may have also sat on a resellers lot) It happens too many times. Hard to say what the history of the car is, but we know the battery was replaced as stated below, so have to assume it has been an existing issue as mentioned below. it could even be something that happened when they replaced the battery. I doubt it had an issue from the factory, but rather something “self inflicted” along the way.
I think @JSwan724 ’s suggestion is on point. You need another set of eyes on that car. Very worst case, get your old SAM and ECU and start back from square one at another dealer or perhaps specialized independent qualified to handle the repair. Even if it means reinstalling your old parts. It’s not like the new parts have made a difference for the better. At least the car should start with your old parts.
Oh man, what a $h!tshow…

I find it insane that thru sheer repair incompetence, you’re re at a point where you have to consider disposing of the car….


Sorry and Good Luck.

 

Thanks for all the advice so far, it's immensely appreciated.

- I fired off an email to the dealer GM, and will be calling them tomorrow as well.
- The dealer contacted the regional reps immediately once they couldn't program the new ECU, they said they can't help, which is why it got run up the chain to Mercedes Germany (programming division, who passed it up to their senior engineers and then never replied).
- Supposedly even with the old ECU and SAM in place, the car is now showing a myriad of errors, including the alternator. I actually directed them to the wiring loom thread back in November, but they're adamant the wiring loom isn't the issue.
- Regarding sending the car to someone else: They have told me that because a ticket has been raised with Mercedes Germany, they are not allowed to get assistance from anyone outside the dealership until they receive a reply.

Frankly this will be the last Mercedes I ever buy, and I cannot believe they have left me in this situation. I have been exceptionally patient with them, and have never hounded them regarding the issues. Yet now, since Mercedes CAC won't even reply to emails/calls about resolving the issue or buying me out of the car, I'm left with the option of taking a $50-60k loss just to get rid of it. In this market, that's like walking away from $100k since just about everything else from Porsche, Mclaren, Ferrari etc are overpriced by at least 20-30%.

 

Tell them you want to look in the trunk for something. Open up the compartment on the left hand side of the trunk and remove the First Aid kit. Take a powerful led torch and throughly check every cable and wire that you can see, especially those that run close over one of the metal braces. Look for any sort of fraying, no matter how small.

Do not let them tell you there’s nothing wrong with the wiring harness and accept it, until you account for the above yourself.

 

Have you posted in the AMG Private Lounge? You won't reach anybody from AMG here, and I don't think any of us can help you with this. Outside of selling the car for parts or getting legal help to pressure MB USA and the dealership into taking the car off your hands, I would recommend you reach out to them via the PL. The AMG team is actually active on the PL forum and they help folks with issues get to the right people within AMG. It's the most direct line for AMG owners to AMG itself.

 

Thank you for the recommendation, I have posted it up in the general discussion section.

 

@DaveH - GTR sad to hear you're going thru this with your car. My mechanic, Max owner of MBenz Motorsport in Miami Lakes, Is a master AMG tech. some MB dealerships ask him advice on how to fix major electrical problems. I remember he found a problem in a benz in 1 day that the dealership couldn't fix in 2 months. Turns out there was a kill switch installed somewhere in the wiring loom. anyways, DM me and I can connect you with him.

 

"IFIXIT" let me know if you need help,

Best HK

 

@DaveH - GTR I Spoke to my Mechanic. He confirmed the notes are locked inside XSENTRY. Appears only someone with engineering level access can see the notes. Sorry you're going thru this man!

 

Extremely grateful for the assistance, hopefully we get some kind of resolution soon.

 

Which dealer?

 

At this time I’d prefer not to reveal that.

I sat down with the GM and apparently some progress has been made on the car. They’re also willing to buy me out but at a $40k loss to me.

 

Agreed progress but not where you want to be. Check the current retail comps on the car and see how far off they are.

I have also found that they may do better price/value wise if you trade it in for another vehicle.

The back up is to let Hendrik Koster in Texas offer try and fix it. He has truly done some amazing stuff that dealers just can’t seem to resolve.

Pleaae be sure your dealings are only with the GM going forward.

Good Luck

 

if not able to invoke any Lemon Law (states vary with interpretation, ie California has LL applicable to Used vehicles as well), and if at an impasse, with only dealership offer resulting in 40K loss to you,
see if perhaps BenzNinja can help, as this may be a complex coding/programming issue at which he is reportedly very good at resolving

Other options, both in Texas:
Christopher Manning, renown AMG Master-Tech, i believe works out of MB at Plano, TX (Instagram handle: "doctoramg")
Hendrik Koster, as aformentioned

 

Renntech could help, but not under warranty!