Possible issue with Renntech HHT
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Joined: Feb 2019
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2019 E63s
Possible issue with Renntech HHT
Good evening everyone, I’ve had a renntech HHT on my 19 E63s for several months now and today I experienced my first issue. While driving on the freeway (in comfort mode) the car suddenly lost power, the dash messages read(I think); rear differential in operational, esc in-operational. The cars rpms were hovering around 1k and the gas peddle was not responding. Lucky I was able to get to the shoulder safely. I turned the car off then back on and everything was fine, I was hoping someone has some experience with this or a suggestion, Car has no other mods just the stage 1 HHT purchased from Renntech. The car has been reflashed and is driving just fine. Any help would be great thank you.
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Joined: May 2016
Posts: 669
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From: Houston
19 E63s
Good evening everyone, I’ve had a renntech HHT on my 19 E63s for several months now and today I experienced my first issue. While driving on the freeway (in comfort mode) the car suddenly lost power, the dash messages read(I think); rear differential in operational, esc in-operational. The cars rpms were hovering around 1k and the gas peddle was not responding. Lucky I was able to get to the shoulder safely. I turned the car off then back on and everything was fine, I was hoping someone has some experience with this or a suggestion, Car has no other mods just the stage 1 HHT purchased from Renntech. The car has been reflashed and is driving just fine. Any help would be great thank you.
Joined: Mar 2018
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From: Socal and Norcal
MY17 S63AMG - MBUSA Buyback. MY16 SL63 - Sold MY19 W213 E63s. 2020 W213 E63s Wagon
Spark plugs? I have read on the W212 E63s having that issue with spark plugs. Colder plugs?
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From: Houston
2003 W211 E55, 2003 W220 S600
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Joined: Jun 2016
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From: Canada
2018 GLE63S Coupe, 2018 E63s
Same issue
I have had this issue for a while now. Went into MB dealership and they replaced the rear diff cap.
Drove for a few days and the problem came again, the dealership then replaced the whole diff!!
Drove again for a few days, the problem is back, the software was updated..
Drove again same day.. same message popped back.
Here’s why its happening and I have avoided the message coming back again for the past 2 weeks.
When you drive on the highway around 120-160km/h in comfort and remove your foot off the gas, the “glide” or sailboat icon appears where it shuts the gears off, when you put your foot back on, the rear diff error pops back, you could almost feel the teeth of the rear diff finding it hard to engage.
Solution?
Have renntech disable your “start/stop” feature which they can do, you will not face this issue again. I turned mine off manually and the issue has not repeat itself.
IMHO, I find it utterly useless that due to north american requirements, these german v8s have to add these features in! Best of luck!
Drove for a few days and the problem came again, the dealership then replaced the whole diff!!
Drove again for a few days, the problem is back, the software was updated..
Drove again same day.. same message popped back.
Here’s why its happening and I have avoided the message coming back again for the past 2 weeks.
When you drive on the highway around 120-160km/h in comfort and remove your foot off the gas, the “glide” or sailboat icon appears where it shuts the gears off, when you put your foot back on, the rear diff error pops back, you could almost feel the teeth of the rear diff finding it hard to engage.
Solution?
Have renntech disable your “start/stop” feature which they can do, you will not face this issue again. I turned mine off manually and the issue has not repeat itself.
IMHO, I find it utterly useless that due to north american requirements, these german v8s have to add these features in! Best of luck!
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2018 W213 E 63 S AMG Sedan
Hmm... there's no way these cars can update themselves over the air, right?
I don't have the exact issue you do, but my car was tuned for a while using what I'm guessing is the same as Renntech's hand-held-tuner (which I'm guessing is MyGenius?) and it was fine for months.
Now all of a sudden, I get that "rear diff inoperational" message too randomly. Sometimes I get it, sometimes I don't. I haven't found the root cause yet...
I don't have the exact issue you do, but my car was tuned for a while using what I'm guessing is the same as Renntech's hand-held-tuner (which I'm guessing is MyGenius?) and it was fine for months.
Now all of a sudden, I get that "rear diff inoperational" message too randomly. Sometimes I get it, sometimes I don't. I haven't found the root cause yet...
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From: Land of 10,000 lakes
AMG GTC Roadster, E63s Ed.1, M8 Comp. Coupe
Perhaps unrelated but I have seen the same message pop-up occasionally since new with zero impact to the behavior of the car. Car is stock and it never dislayed past a restart. I just consider it a random nuisance message tripped by software, not sensors...
Member
Joined: Nov 2012
Posts: 86
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2012 Mercedes CLS550 4Matic, 2014 ML550 Diamond White, 2015 SL550 Diamond White
Renntech Tune Causes Problems
I installed a Renntech Tune on my 2012 CLS550 with the hand held tuner. Biturbo V8
Driving at WOT the car would randomly lose significant power and go into limp home mode.
I would have to stop the car, shut off and restart, and things were back to normal.
Also at very high speeds around 95 to 100 mph at WOT the car always lost power suddenly at the exact same speed.
I data logged turbo pressures, and other parameters and could not find any obvious cause.
I worked with the renntech tuning engineer, and finally he suggested I check the version of the Mercedes ECU programming
It happened to be an older version as it was never updated by a dealership. And the Renntech tune was done on much newer versions of the Mercedes ECU programming
The solution was to update my car's ECU programming to the most up to date version. The sudden loss of power incidents stopped happening.
Although occasionally when doing WOT at highway speeds there is a violent jerk as if the engine briefly shuts down and back on again. Very worrying. Rare occurrence but it should never happen
These renntech tunes are NO WHERE NEAR PERFECT. Renntech has very limited staff, knowledge and resources to work all the bugs out of a tune compared to an Auto Manufacturer like Mercedes who has almost unlimited resources to fine tune the engine and transmission calibrations. There are probably dozens of Mercedes engineers working on just the programming/ of the engine control unit and getting the "tuning" right.
Compared to a handful of people working on a tune at renntech
Driving at WOT the car would randomly lose significant power and go into limp home mode.
I would have to stop the car, shut off and restart, and things were back to normal.
Also at very high speeds around 95 to 100 mph at WOT the car always lost power suddenly at the exact same speed.
I data logged turbo pressures, and other parameters and could not find any obvious cause.
I worked with the renntech tuning engineer, and finally he suggested I check the version of the Mercedes ECU programming
It happened to be an older version as it was never updated by a dealership. And the Renntech tune was done on much newer versions of the Mercedes ECU programming
The solution was to update my car's ECU programming to the most up to date version. The sudden loss of power incidents stopped happening.
Although occasionally when doing WOT at highway speeds there is a violent jerk as if the engine briefly shuts down and back on again. Very worrying. Rare occurrence but it should never happen
These renntech tunes are NO WHERE NEAR PERFECT. Renntech has very limited staff, knowledge and resources to work all the bugs out of a tune compared to an Auto Manufacturer like Mercedes who has almost unlimited resources to fine tune the engine and transmission calibrations. There are probably dozens of Mercedes engineers working on just the programming/ of the engine control unit and getting the "tuning" right.
Compared to a handful of people working on a tune at renntech
Member
Joined: Nov 2012
Posts: 86
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2012 Mercedes CLS550 4Matic, 2014 ML550 Diamond White, 2015 SL550 Diamond White
The Limp Home Mode, And the engine cutting out never happened before the Renntech Tune.
So I dont think its the gas pedal position sensor in my case
So I dont think its the gas pedal position sensor in my case
Member
Joined: Nov 2012
Posts: 180
Likes: 39
From: Orlando, FL
2017 SQ5 / 2012 Ferrari FF
A little late to this but have the same problem. With RENNtech tune in comfort on highway, it’ll go to limp mode after 20-30 minutes. Coast to shoulder, turn off, turn on, resets. When flashed back to stock, never ever ever has happened. When on the RENNtech tune and in anything other than comfort (sport/sport plus/race/individual set up to sport with comfort suspension), it doesn’t happen. Asked RENNtech and they said they hadn’t heard of that issue (but the previous owner who had it tuned specifically brought it up). Not sure if there’s a fix or not, I’ve just been stuck driving in stock ecu mode to make sure it doesn’t happen on accident with someone else driving or when there’s traffic. Now that I’m out of warranty anyway I’m switching tunes. Was super surprised renntech had this issue-they are supposed to be the ones who err on the side of drivability/OEM-ness.
Member
Joined: Nov 2012
Posts: 86
Likes: 2
2012 Mercedes CLS550 4Matic, 2014 ML550 Diamond White, 2015 SL550 Diamond White
Try updating your engine calibration to match renntech tune better
My solution was to update my engine calibration to match the renntech tune properly. If that doesn't work. DEMAND YOUR MONEY BACK FROM RENNTECH. Talk and email the tuning engineer directly. Not the salesman. Let us know what happens
Member
Joined: Nov 2012
Posts: 180
Likes: 39
From: Orlando, FL
2017 SQ5 / 2012 Ferrari FF
I’ve had a RENNtech tuned car before and it wasn’t problematic at all, so this is an outlier, but wanted to share feedback on here. I think I’ll get a fresh start with a different ecu tune to go with a cpc/tcu tune and have started asking around to the other shops I’ve used before (eurocharged, ECC, etc)
Member
Joined: Nov 2012
Posts: 180
Likes: 39
From: Orlando, FL
2017 SQ5 / 2012 Ferrari FF
Update-got a CPC tune, and tried the RENNtech tune again…still broken. With the RENNtech tune, on the highway at steady speeds in comfort mode, goes into limp mode and everything shuts down. Glad I could make it to the shoulder. Goes away after a restart, but I was hoping that after getting a CPC tune that maybe that would have resolved it. Alas. Will definitely be getting a tune from a different vendor - this is wild, have never had an experience like this with a ‘premium’ stage 1 tune. Here is a video of it once I pulled over and put it in park. Revs bouncing, all the error messages, no throttle input allowed.
