Sudden lack of noise when downshifting C43 AMG
Thread Starter
Newbie
Joined: Jan 2020
Posts: 4
Likes: 0
C43 AMG
Sudden lack of noise when downshifting C43 AMG
Bought at ‘18 Mercedes C43 last week with 3700 miles on clock. It’s been amazing fun all week, I’ve loved it. Usually when it’s in sport + and I brake, it down shifts through the gears and makes a lovely revving growling noise and crackle at each gear it drops. A real head turner coming up to traffic lights etc. However today I drove economically over a long distance as it was 50mph average speed the whole way. Now, for some unknown reason, when I’ve put it back into sport + and braking, there’s no sound whatsoever. It downshifts as it should but just does so extremely quietly with no fuss like it’s in comfort mode. No over revving and no lovely loud growl and crackles at each gear drop. I’m devastated.
Honestly it’s taken away so much of what I love about this car. Can someone please shed some light on why this has happened and help me resolve?
TIA
Honestly it’s taken away so much of what I love about this car. Can someone please shed some light on why this has happened and help me resolve?
TIA
Last edited by Brad1511; Jan 22, 2020 at 06:01 PM.
Super Member
Joined: May 2010
Posts: 829
Likes: 190
2017 C43
Try flooring it a few times upto 3rd gear in sport+ and let go, off the gas pedal quickly and floor it again. Do a few of those in succession.
It’s probably still “learning” mode since you’ve only had it a week, and stuck in learning your eco driving mode.
It’s probably still “learning” mode since you’ve only had it a week, and stuck in learning your eco driving mode.
Super Member
Joined: Dec 2016
Posts: 797
Likes: 141
2018 C43
On my 18 with PE, you get 2 noises in all modes. 1st is the crackle and pops specially more so in S+. When coming to a stop, it would downshift some times crackle and popping but not all the time. 2nd is regular loud exhaust notes, S+ is louder.
Do a transmission reset and leave it on S+ for next few days and drive like you stole it, if you feel your car is shifting too eco.
Do a transmission reset and leave it on S+ for next few days and drive like you stole it, if you feel your car is shifting too eco.
Thread Starter
Newbie
Joined: Jan 2020
Posts: 4
Likes: 0
C43 AMG
On my 18 with PE, you get 2 noises in all modes. 1st is the crackle and pops specially more so in S+. When coming to a stop, it would downshift some times crackle and popping but not all the time. 2nd is regular loud exhaust notes, S+ is louder.
Do a transmission reset and leave it on S+ for next few days and drive like you stole it, if you feel your car is shifting too eco.
Do a transmission reset and leave it on S+ for next few days and drive like you stole it, if you feel your car is shifting too eco.
MBWorld God!
Joined: Dec 2019
Posts: 32,347
Likes: 6,319
Senior Member
Joined: Mar 2018
Posts: 323
Likes: 103
From: Central Florida
'15 C400 and '15 ML350
The car makes the pops by spraying extra fuel at those points. If you drive it differently, change the battery, tune it, change to E40, have drastic weather change, etc. Basically anything that messes with the long term fuel trims, the car will not have the same pops until it learns and adjusts back to where it can safely overrun the fuel for pops.
As others have said, you can try driving in S+ more or just give it a day or so. I wouldnt reset the trans unless its not shifting correct, the TCU learning doesnt control the pops only clutch pressure and valve fill times.
As others have said, you can try driving in S+ more or just give it a day or so. I wouldnt reset the trans unless its not shifting correct, the TCU learning doesnt control the pops only clutch pressure and valve fill times.
Last edited by MatthewJ; Jan 23, 2020 at 09:03 AM.
Trending Topics
Thread Starter
Newbie
Joined: Jan 2020
Posts: 4
Likes: 0
C43 AMG
The car makes the pops by spraying extra fuel at those points. If you drive it differently, change the battery, tune it, change to E40, have drastic weather change, etc. Basically anything that messes with the long term fuel trims, the car will not have the same pops until it learns and adjusts back to where it can safely overrun the fuel for pops.
As others have said, you can try driving in S+ more or just give it a day or so. I wouldnt reset the trans unless its not shifting correct, the TCU learning doesnt control the pops only clutch pressure and valve fill times.
As others have said, you can try driving in S+ more or just give it a day or so. I wouldnt reset the trans unless its not shifting correct, the TCU learning doesnt control the pops only clutch pressure and valve fill times.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Senior Member
Joined: Mar 2018
Posts: 323
Likes: 103
From: Central Florida
'15 C400 and '15 ML350
Trans learning reset is fairly easy to do, but with only 3,700 miles it probably doesnt have enough data/adjustments to notice a difference. It happens very slowly.
I would drive like normal for a few days (in S or S+ , whatever you typically use) and if it doesnt improve then try the reset.
Also FWIW on the next road trip, activating cruse control in sport should change the behavior so the car selects the highest gear for fuel econ. The peddle sensitivity will still be there vs the "numb" effect of E mode. Should achieve the same mpg on the trip. It would then take either aggressive driving or a switch from S to C, back to S for the car to go back to holding gears.
Assuming the programming on the 2018 is the same as 2015.
I would drive like normal for a few days (in S or S+ , whatever you typically use) and if it doesnt improve then try the reset.
Also FWIW on the next road trip, activating cruse control in sport should change the behavior so the car selects the highest gear for fuel econ. The peddle sensitivity will still be there vs the "numb" effect of E mode. Should achieve the same mpg on the trip. It would then take either aggressive driving or a switch from S to C, back to S for the car to go back to holding gears.
Assuming the programming on the 2018 is the same as 2015.
Thread Starter
Newbie
Joined: Jan 2020
Posts: 4
Likes: 0
C43 AMG
Thanks for all the help. Really appreciate it. Taken it for a long drive today where I very much pushed it to its limits in sport +. Seems to be a little better but only making noise when downshifting some of the time. Will keep at it over the next few days and update. Seen a lot of similar threads that nobody can seem to find a definitive cause led to people going to MB and being advised to have a software update on the coupe’s transmission bit that has made their cars quieter than ever!
Junior Member
Joined: Apr 2016
Posts: 28
Likes: 1
C450 AMG
Hey guys, I got my 2019 c43 tuned end of Dec by Eurocharged. However, since then i have been driving very economically, as I had a few long haul family drives, and we have had bad weather (snow). Im worried my car as "learned" this.
Would I benefit at all from doing this retset? Does the method work on 2019 9 speed trans? I read somewhere i can unhook the neg terminal on battery and it resets trans as well.
Suggestions?
Would I benefit at all from doing this retset? Does the method work on 2019 9 speed trans? I read somewhere i can unhook the neg terminal on battery and it resets trans as well.
Suggestions?
