2017 CLS63S Issues
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CLS63S, Sprinter 2500
2017 CLS63S Issues
Hello, I have a 2017 CLS63S I have had for close to 2 years now. The car is still covered under CPO warranty, unfortunately I have had no luck with Mercedes diagnosing the problems I am having with the car. On two occasions now while driving, the area of my gauge cluster where it shows my gear has gone out and I can not accelerate. The engine revs but the car does not put the power down. I have this on video both times. Another issue I am having is when the car shifts from 3rd to 4th I notice a loss of power, each shift up until this feels smooth. I also have a video of this but not sure how evident it is in video. There is also a new issue that has risen, if I am at a dead stop and put my foot to the the floor, the car seems sluggish for the first 20mph. It revs up to about 2k rpm and holds it for a second before the power really kicks in. On top of all this there is also a whining noise I notice in lower gears at full throttle, sounds very similar to a supercharger. I have been trying to resolve the issues with this car since the day I bought it. If anyone has had a similar experience or has heard of these issues please let me know. Can PM videos if anyone is interested. Thank you
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
This might be one of those "disconnect the negative terminal on the battery for an hour" things. Let the computers reset and see what warnings come back. Also, as indicated above, make sure the dealer has flashed all of the correct software updates to the car.
maw
maw
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2018 CLS63s 4Matic+
Same issue on my 2018, even after fresh transmission rebuild
Hello, I have a 2017 CLS63S I have had for close to 2 years now. The car is still covered under CPO warranty, unfortunately I have had no luck with Mercedes diagnosing the problems I am having with the car. On two occasions now while driving, the area of my gauge cluster where it shows my gear has gone out and I can not accelerate. The engine revs but the car does not put the power down. I have this on video both times. Another issue I am having is when the car shifts from 3rd to 4th I notice a loss of power, each shift up until this feels smooth. I also have a video of this but not sure how evident it is in video. There is also a new issue that has risen, if I am at a dead stop and put my foot to the the floor, the car seems sluggish for the first 20mph. It revs up to about 2k rpm and holds it for a second before the power really kicks in. On top of all this there is also a whining noise I notice in lower gears at full throttle, sounds very similar to a supercharger. I have been trying to resolve the issues with this car since the day I bought it. If anyone has had a similar experience or has heard of these issues please let me know. Can PM videos if anyone is interested. Thank you
Out Of Control!!
Joined: Apr 2019
Posts: 11,823
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
standard fare...
Hello, I have a 2017 CLS63S I have had for close to 2 years now. The car is still covered under CPO warranty, unfortunately I have had no luck with Mercedes diagnosing the problems I am having with the car. On two occasions now while driving, the area of my gauge cluster where it shows my gear has gone out and I can not accelerate. The engine revs but the car does not put the power down. I have this on video both times. Another issue I am having is when the car shifts from 3rd to 4th I notice a loss of power, each shift up until this feels smooth. I also have a video of this but not sure how evident it is in video. There is also a new issue that has risen, if I am at a dead stop and put my foot to the the floor, the car seems sluggish for the first 20mph. It revs up to about 2k rpm and holds it for a second before the power really kicks in. On top of all this there is also a whining noise I notice in lower gears at full throttle, sounds very similar to a supercharger. I have been trying to resolve the issues with this car since the day I bought it. If anyone has had a similar experience or has heard of these issues please let me know.
Can PM videos if anyone is interested. Thank you
Can PM videos if anyone is interested. Thank you
Where you should draw the line is with LIMP MODE: this can lead to fatality in rush hour traffic.
Get this worked on by your local MB experts:
- Start with a chassis comprehensive scan
- Focus on most unstable CAN Modules
- Deal with marginal voltage issues
When the warranty expires is when work stops regardless of known pre-existing defect.
Then you can experiment with your spongy throttle out of warranty.
Last edited by CaliBenzDriver; Mar 19, 2026 at 08:51 PM.
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2018 CLS63s 4Matic+
Could this code have something to do with it?
I read your documented feedback. A lot of these issues are standard built-in features, in particular "below 2,000.Rpm...".
Where you should draw the line is with LIMP MODE: this can lead to fatality in rush hour traffic.
Get this worked on by your local MB experts:
When the warranty expires is when work stops regardless of known pre-existing defect.
Then you can experiment with your spongy throttle out of warranty.
Where you should draw the line is with LIMP MODE: this can lead to fatality in rush hour traffic.
Get this worked on by your local MB experts:
- Start with a chassis comprehensive scan
- Focus on most unstable CAN Modules
- Deal with marginal voltage issues
When the warranty expires is when work stops regardless of known pre-existing defect.
Then you can experiment with your spongy throttle out of warranty.
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Newbie
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2018 CLS63s 4Matic+
Was the issue always there?
Hello, I have a 2017 CLS63S I have had for close to 2 years now. The car is still covered under CPO warranty, unfortunately I have had no luck with Mercedes diagnosing the problems I am having with the car. On two occasions now while driving, the area of my gauge cluster where it shows my gear has gone out and I can not accelerate. The engine revs but the car does not put the power down. I have this on video both times. Another issue I am having is when the car shifts from 3rd to 4th I notice a loss of power, each shift up until this feels smooth. I also have a video of this but not sure how evident it is in video. There is also a new issue that has risen, if I am at a dead stop and put my foot to the the floor, the car seems sluggish for the first 20mph. It revs up to about 2k rpm and holds it for a second before the power really kicks in. On top of all this there is also a whining noise I notice in lower gears at full throttle, sounds very similar to a supercharger. I have been trying to resolve the issues with this car since the day I bought it. If anyone has had a similar experience or has heard of these issues please let me know. Can PM videos if anyone is interested. Thank you
nother follow up from me, did this start happening at random for you or was it always there? Mine consistently happens under light load and right at 2k RPM
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Out Of Control!!
Joined: Apr 2019
Posts: 11,823
Likes: 6,707
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
up the creek
The one code I've consistent had with the car is C16887 with the MFK - "communication with the electronic ignition lock has a malfunction". It's probably a long-shot, but could this in any way be related to the gear disappearing and acceleration cutting out for a few seconds? I'll note that this cut out only happens right at 2k RPM, typically under very light load. Nothing else disappears from the cluster other than the gear, the temps and speed stay visible. I can floor the accelerator during the period where it cuts out and nothing happens. Let me know if you guys have any thoughts - I have a full warranty through carmax so I'll likely bring it back in to get sorted, but I'd love to avoid that if possible.
It's not rocket science to fix BUT it may soon become a money pit opportunity hence got Carmax traded.
This reads like a basic CAN disruption.
Tranny is forced to limp mode when gear selection goes missing Or gear selection goes blank when TCU gets unstable.
Nearly no big deal: this does not call for a tranny rebuild job.
If you don't have an MB scanner someone is gonna need to identify the root cause without replacing too many working modules.
Your summary captures this well :
- PRND display goes missing
- Engine throttle limp modes
- MFK - EIS lost COM... CGW??
I can see this repair ballpark from 1 to $4k.
Last edited by CaliBenzDriver; Apr 28, 2026 at 04:27 PM.
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2018 CLS63s 4Matic+
This being a CARMAX warranty... you're gonna have to decide WHEN to return this limp-mode lemon if they can't get it fixed.
It's not rocket science to fix BUT it may soon become a money pit opportunity hence got Carmax traded.
This reads like a basic CAN disruption.
Tranny is forced to limp mode when gear selection goes missing Or gear selection goes blank when TCU gets unstable.
Nearly no big deal: this does not call for a tranny rebuild job.
If you don't have an MB scanner someone is gonna need to identify the root cause without replacing too many working modules.
Your summary captures this well :
I can see this repair ballpark from 1 to $4k.
It's not rocket science to fix BUT it may soon become a money pit opportunity hence got Carmax traded.
This reads like a basic CAN disruption.
Tranny is forced to limp mode when gear selection goes missing Or gear selection goes blank when TCU gets unstable.
Nearly no big deal: this does not call for a tranny rebuild job.
If you don't have an MB scanner someone is gonna need to identify the root cause without replacing too many working modules.
Your summary captures this well :
- PRND display goes missing
- Engine throttle limp modes
- MFK - EIS lost COM... CGW??
I can see this repair ballpark from 1 to $4k.
Out Of Control!!
Joined: Apr 2019
Posts: 11,823
Likes: 6,707
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
limp mode repair
I'm confident someone can figure it out - I don't have an Autel or Xentry which is likely what this needs to diagnose. I've been reluctant to take the car back in simply because I've been enjoying it after the transmission was completely rebuilt under warranty. The car was down for about 6 weeks working through that. Fortunately, everything else is perfect and the repairs won't cost me a dollar, it's just the inconvenience. I appreciate the input!
This CAN disruption could be as simple as a low battery charge... few techs want to diagnose a cheap warranty repair. Next time may be an ECU plus couple injectors...
Even if you could pinpoint the exact cause yourself, this would hardly alter warranty course.
Last edited by CaliBenzDriver; Apr 28, 2026 at 06:00 PM.
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2018 CLS63s 4Matic+
OMG... your issue already got diagnosed for a complete tranny job - Fortunately you did not pay for the unnecessary call.
This CAN disruption could be as simple as a low battery charge... few techs want to diagnose a cheap warranty repair. Next time may be an ECU plus couple injectors...
Even if you could pinpoint the exact cause yourself, this would hardly alter warranty course.
This CAN disruption could be as simple as a low battery charge... few techs want to diagnose a cheap warranty repair. Next time may be an ECU plus couple injectors...
Even if you could pinpoint the exact cause yourself, this would hardly alter warranty course.
Out Of Control!!
Joined: Apr 2019
Posts: 11,823
Likes: 6,707
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
We shall see! To be clear the rebuild was 100% necessary, I had violent chatter under heavy load, a whine and VERY clunky shifts. It's smooth as butter now, just hoped the whole "gear disappearing / cutting out" thing would be solved during the process.
I'll keep the thread posted when I get a confirmed diagnosis or fix. If you see an AMG on carmax with about 60k miles, it probably needs a trans LOL.
I'll keep the thread posted when I get a confirmed diagnosis or fix. If you see an AMG on carmax with about 60k miles, it probably needs a trans LOL.
Were the PRND + Limp mode present before or did this show up recently ?
It may be the newly rebuilt TCU module has issues. Faults would point that way.
Newbie
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2018 CLS63s 4Matic+
Exactly, I'm sure the previous owner launched it one too many times. Thank god for the warranty. The issue was there before and after.
Out Of Control!!
Joined: Apr 2019
Posts: 11,823
Likes: 6,707
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
resume warranty repairs
- 1 - Diagnose the faults from a chassis report.
- 2 - Test the top suspects before rushing to conclusions.
Provide a precise list of issues to help guide work order while you can:
- MFK drops COMS with EIS
- missing PRND display
- Limp mode near 2kRpm
- ....
Last edited by CaliBenzDriver; Apr 28, 2026 at 11:43 PM.
