Cpbball3

I had 21K miles on my C300 Sport 4MATIC. I felt like when I first got the car it was much faster and I was more impressed with the speed. Yesterday I read about the "reset the TCU" trick. I said I would try it out and report back the results. All I can say is WOW. The difference is clearly noticeable from the second you back out of the driveway. The car has less lag when I chose to accelerate, etc. I am very happy and this was a great tip whoever researched it! I suggest you all try it out. Yes, you can hear a little bit of engine noise for 3 seconds after you reset the TCU if it is quiet enough.

(1.) Turn the ignition key to the on (not start) position.
(2.) Press the gas pedal to the floor and hold for five seconds.
(3.) Turn the key to the "off" position (don't remove the key), then release the gas pedal.
(4.) Wait at least two minutes for TCU to reset. (key in)

Niti24

I still haven't been able to make it work

Samieee

I've tried it several times and still don't feel anything

Cpbball3

There is a possibility that some transmissions do not need to be reset? Do you both have 08's?

nukefixer

I have a 2008 sport model and it worked for me!
Just exactly like the instructions, you can definitely tell the difference, especially starting to move, much more responsive to the gas peddle!

chokaay

All MB transmissions (at least for the last 10 years) are adaptive, thus all of them can have their TCU reset. I have made some modifications to the original instructions in RED:


It can get quite hot sitting in a sealed up car for a few minutes, so you may not want to do it outside in the sun...

johnlk25

I drive in the comfort mode to where the car starts off in second gear because I dont like the jerkiness of sport mode, so I dont know if doing this would be the right thing for me.

Are there any other benefits to doing this? By resetting this, isnt the car going to have to learn the characteristics of how you drive all over again?

I guess I'm just trying to figure out what the benefits are to doing this?

chokaay

Yes, the car will learn the characteristics of how you drive all over again (which is why some people reset their TCU/ECU every month).

The benefits are that the car resets its throttle settings to default... hence faster response times, snappier acceleration, and more sensitive gas pedal (since your driving style hasn't "influenced" these settings yet).

Honestly, if you're at least 90% pleased with how your car is performing right now, I recommend you do NOT reset your TCU/ECU. Doing so may cause your vehicle to eventually learn and perform less-satisfactory than what you have right now. One of my E350's I don't touch since I felt the TCU was awesome from the start. The other one I reset a couple months ago and now it's better (but not perfect... and I don't think it'll ever be 100% perfect in my eyes). Too bad MB doesn't make the adaptive throttle have an on/off setting (off being maximum performance all the time... but I guess that would basically be similar to setting the car in "S" mode and resetting the TCU all the time).

coolvi

It only makes more sense if you live under certain climates that require different driving styles during different seasons. For example, harsh winter versus summer driving. I reset mine early spring this year and I figured resetting once a year in spring time is pretty much all I'll need for it to disgard all the sluggish/conservative winter driving info.

Otherwise, it'll just simply adapt to your driving style and unless you're going to drastically change the way you drive, it just doesn't make a lot of sense.

johnlk25

Do you have to reset it for each mode (comfort and sport). What I'm getting at is that if you reset it and it wipes out everything that the car has learned in comfort and sport, then it wouldnt matter which mode you use, they are both going to be the same. You see what I'm getting at?

So if I reset it and it wipes out everything that the car has learned, then I proceed to drive in comfort mode for a month, then if I switch to sport mode, its not going to drive any different.

chokaay

C and S modes are not the same. C mode starts the car out in 2nd gear and shifts at lower RPM's than S mode. S mode starts the car in 1st gear and shifts at a higher RPM and more aggressively/quickly. Fuel consumption by the engine may also be dependant on the modes. These facts will not change.

What WILL change is how the car judges when to switch gears based on your accerlerator actions (and maybe some other inputs).

johnlk25

Thats my point exactly. If you have been driving your car for any extended period of time, it has obviously learned your driving habits. And the way you drive is the way you drive.....its not gonna change, so why reset everthing that the car has learned just to have it learn all over again? Just doesnt make sense to me.

I could see that it would make sense in some situations like if you obtained your car used, or you let some else drive your car for an extended period of time. But if you have had the car for at least 6 months and you have been the only one driving it, then why reset it??? Just to get a "temporary" boost in performance?

chokaay

Yup... that's why most people do it.

It really sucks when for 5 days out of the week you only drive the vehicle in rush hour traffic and the car "learns" that you really like to drive 25mph for hours, accelerating slowly and coasting 99% of the time, and that you don't ever accelerate quickly or anything. It must think the driver is a 90-year-old senior citizen (no offense to anyone) who likes to take their time and drive significantly under the speed limit... thus prioritizing slow-but-steady acceleration and hesitating a couple seconds at any quick maneuver (like slamming the pedal to the metal) because it assumes it's a nervous "twitch" or seizure and that the driver really didn't intend for that to happen.

Personally, when I trained my TCU/ECU, I tried to only drive that particular vehicle on the weekends in no traffic whatsoever... and drive my other already trained vehicle during the weekdays. However, not everyone has access to 2 vehicles to do this, hence resetting the TCU/ECU is a way to bring the car back to how it was when you first bought it (and to inject some excitement into your driving experience).

IMHO I really think that MB would be better off if they allowed the user to toggle this setting on/off in the car's menu... or at least allow a way for the dealership to disable the "adaptive" part of the transmission using STAR so that the vehicle doesn't adapt to traffic conditions or different drivers driving the vehicle, and just drove at its default "maximum" performance settings all the time (basically perform like the vast majority of other vehicles on the road today... they don't have "adaptive" transmissions and drive at their default factory settings).

gwai_jai

thanks for the tipss!!... i just did it yesterday night and it makes such a big difference

johnlk25

I agree with you about disabling it and just drive the way that you want to without it having to learn "bad habits"....lol. Kind of the same way that you can disable the traction/stability control.

coolvi

Agreed. Plus my assumption of the TCU settings' logic is that it resets to an average point so there is a shorter learning curve to either end of the scale. If that is true, that means the car could become more responsive if, for example, it is used mainly on the tracks; The only reason we are only seeing it going downhill is due to the slow city traffic, as you mentioned, so pretty much all of our TCU's are trained to make it easier to control the car.

The ability to actually disable it would be nice, but I would not mind having the TCU pre-programmed with certain settings. For example, aggressive, moderate, and conservative presets, plus individualization 1, 2, and 3, etc...

kevink2

Looks like you are using my modified TCU reset (next link below), based on your underline use above where I mostly quoted the standard TCU reset found in "secrets" thread.

https://mbworld.org/forums/c-class-w...t-booster.html <- My Modified TCU Reset Method

For automatics, there is a hard spot at about 75-80% pedal travel. During my TCU reset, [B] I press the pedal just to the hardspot [/, rather than flooring it B].
Cpbball3 , is this how you did the TCU reset?

Again, I'm not sure if this proceedure just resets wot and idle positions for the ecu and tcu, or if it also clears bad adaptive learnings.

ps, related "sprint" white paper on pedal output volts vs position:

http://peony888.com/VS/SprintBooster.pdf (see fig 1 ) My "revised TCU reset" puts the throttle disc at 100% open, with pedal travel only at about 80% of full travel to the floor. This is similar to the sprint boost install, but w/o the 30+ percent in signal increase ... just compression of the "x axis" in fig 1.

Bottom line was much better response to pedal motion. More fun, but not faster in 0-60 or 1/4 mile ET, which was the point of the white paper.


.

kevink2

Cpbball3 answered this in a pm:

"I pressed the pedal all the way to the floor. I am not sure that it matters. I read your post and see your logic. However, maybe as long as you push the pedal down for 5 sec, while the keys are in that position in the car, it will reset automatically. I did notice a huge difference though. The car had much more raw power and I loved it."

I think owners make a mistake and don't leave the key in during the last step #4.

He used the standard method (floored it). I think even more pep will be found using my method: just pressing pedal to hard spot.

.

ronjack

Just reset mine, what a difference.

jlb0125

I did mine earlier today. It seems to make a difference. Time will tell.

OvOMitch

Sorry to bring this thread back, didn't wanna get scolded for not using the search bar :O

But can I do this to a loaner vehicle without getting in trouble by the dealer? My C250 is in for service and I am currently driving a C300 4matic. At first I was excited to see the performance difference, but it feels extremely sluggish unless I really get on it. My C250 feels ALOT more agile, but maybe this will help?

C3504M

i would like to know if you can do it with push button start?

SCTinkering

Follow the instructions for removing the Keyless-Go button in the manual, reset your TCU then reinstall the Keyless-Go button.

Frnak

Even though this is an older thread I thought it was worth bringing up again. My 2013 C 250 has been getting increasingly slow to downshift in E along with a spongy gas pedal. Before calling the dealer I did a search here and found a couple of threads outlining the reset procedure. I performed the reset yesterday afternoon and wow, what a difference.
As has been argued in other posts, I'm not certain that the reset does anything for the trans but it does substantially increase the engine's low end grunt which allows you to pull away cleanly after a slowdown to 10 to 20 MPH. Even if I have to do this every few months, it's worth the 5 minutes it takes to restore the performance.


Mega thanks to whoever discovered this and first posted it.
Frank

DapperStyle

It is a fantastic tool. I've done it a couple of times, including about 2 weeks ago. This time I felt a massive difference because shortly after resetting it I spent the next half hour driving like a bat out of hell on some mountain backroads. I then turned the car off and turned it back on and voila the car felt the best I've had it since. I'll try to do this monthly if possible.