How to reset Mercedes transmission?

To reset a Mercedes automatic transmission (the adaptive shift values stored in the transmission control unit), turn the key to position 2 without starting the engine, press the accelerator fully to the floor for 15 seconds, turn the key back to position 1 while still holding the pedal, release the pedal, and wait about 2 minutes with the key in the ignition. Then start the car and drive gently: the transmission relearns your driving style over its first 40 gear changes.

Owners of Mercedes-Benz vehicles often complain that the automatic transmission feels heavy and slow on gear changes, or that first gear holds on to very high revs. This reset is the procedure for that, and it applies to many C, E, S, CLK, CLS, CLA, ML, GLK and SLK models from 1995 to 2016.

TL;DR

• Cause: the transmission control unit adapts its shift points to your driving style, and over time can learn late, harsh or slow shifts.
• Fix: key to position 2 (do not start), accelerator fully down for 15 seconds, key to position 1, release the pedal, wait 2 minutes.
• Then drive gently: the transmission re-adapts over its first 40 gear changes.
• Covered models: C, E, S, CLK, CLS, CLA, ML, GLK and SLK, model years 1995 to 2016.
• If shifting is still poor after the reset, have the transmission inspected by a specialist.
• If you drive a Sprinter van, read Mercedes-Benz Sprinter transmission issues instead.

How do you reset a Mercedes transmission step by step?

Table of Content

1. General procedure to reset the adaptive gear system in the Mercedes-Benz transmission control unit (TCU).
2. What are the benefits of performing this procedure?
3. How important is regular preventive maintenance?
4. To which vehicles can this procedure be applied?
5. Conclusion

Source - https://www.interempresas.net/MetalMecanica/Articulos/129168-Weistec-Engineering-satisface-apetito-velocidad-duenos-automoviles-Mercedes-AMG.html

1.General procedure to reset the adaptive gear system in the Mercedes-Benz transmission control unit (TCU).

First of all, we should briefly mention how this system works. The automatic transmission control unit monitors and sends your driving style information to the engine control unit (ECU). Using the signals sent by the accelerator pedal and the throttle body to the control unit, behaviors and trends are generated about your driving style, this allows the control unit to set different shifting points at different revolutions per minute (RPM). On multiple occasions, you can realize that in first gear it is kind of difficult to move the vehicle and the change is made at very high revolutions per minute, this triggers a slowness feeling and increases your fuel consumption. If the car drops into neutral while driving rather than shifting late, that is a different fault: see Mercedes GLA shifts to neutral when driving.

Step 1

Make sure your vehicle is fully parked and on a flat surface. As a first step, we must place the key on the ignition switch, it is necessary to turn the key to position 2 (ON) and we will be able to visualize that all the emergency lights of our panel will be turned on. Note: Do not start the vehicle.

Step 2

Fully press the accelerator pedal for 15 seconds. Moving the throttle pedal throughout its path will activate the Kick Down switch. It is necessary to keep the accelerator pedal pressed during this step.

Source - nettcontrol.com

Step 3

Even with the accelerator pedal pressed, turn the key to position 1 (OFF). The key must remain on the ignition switch of the vehicle during this step.

Source - club.autodoc.es

Step 4

Release the throttle pedal. During this step, the key must remain on the ignited subway of the vehicle.

Step 5

You should remain inside the vehicle for about 2 minutes without taking any action. During this step, it will not be possible to exit the unit or interact with any device inside, as it is at this time that the transmission control unit and the engine control unit are communicating to reset the device’s factory parameters. Note: It is important to keep the key on the power switch during this step.

Step 6

After these 2 minutes of waiting, turn on your vehicle and drive as you normally would for a few minutes.

Note: It is recommended that during this driving test period you do not have a sporty driving or many acceleration points, as the transmission will be adapted according to its first 40 gear changes once the system is reset.

2.What are the benefits of performing this procedure?

Performing this procedure allows the electronic systems of the transmission box, engine, the throttle body, among others; to restore their normal operating parameters and give us a feeling of driving a vehicle out of the agency.

To maintain the performance of your Mercedes, it is advisable to perform this procedure every six months or according to the behavioral patterns that you can see in your car.

3.How important is regular preventive maintenance?

Something we should not forget is to visit our authorized service center to perform periodic maintenance services to all the elements that include the transmission system. This action will allow us to avoid any kind of wear failure. The maintenance information for your model is in its operator's manual, which you can find on the Mercedes-Benz USA owner's manuals page.

If the problem persists, an in-depth technical inspection should be carried out by a specialist, as there is a high probability that some of the devices involved in the gear change are damaged or out of operation parameters. Reading the stored fault codes first helps: see the OBD2 troubleshooting guide. For Actros trucks there is a separate procedure in how to reset the Mercedes Actros gearbox.

This procedure is carried out similarly at Mercedes-Benz specialist service centers using specialized equipment. But the results you get will be the same when you do it yourself.

Source - https://www.actualidadmotor.com/9g-tronic-mercedes-caja-automatica-eficiente/

4.To which vehicles can this procedure be applied?

Mercedes-Benz vehicles involved are the following:

1. C-Class (Sedan, Coupe)
2. E-Class (Sedan, Coupe,Cabriolet)
3. S-Class (Sedan, Coupe, Cabriolet)
4. CLK
5. CLS Coupe
6. CLA Coupe
7. ML
8. GLK
9. SLK

And include model years from 1995 up to 2016.

5.Conclusion

The cost-benefit ratio of this type of vehicle and particularly of the Mercedes-Benz brand is quite high, so keeping your vehicle in optimal condition is a primary issue for most users and customers of the brand. There are many advantages that we get from this procedure. In the first instance, we will be able to see a change in the dynamic behavior of the vehicle which is often the most important cause for which we acquire a Mercedes-Benz. Second and no less important, is the decrease in petrol consumption which translates into savings to our portfolios.

References:

1. Mercedes transmission control module (TCM / TCU), BenzWorld forum thread