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  • Mercedes Reset

    Our cars a very complex and when something goes wrong /w them repairs can be daunting, to say the least. Most things that go wrong are controlled by a computer chip call an Electronic Control Unit (ECU). There is a lot of good information in our Owner's Manuals, and I highly recommend that you read it. But for those of us who just want a quick answer to our immediate problem this should be helpful. A friend of mine on another board (Skylaw) put this together and I hope you find it as valuable as I have.

    Windows, seats, mirrors, steering wheel position (easy entry/exit) and the like can be reset by running them fully in one direction, holding the switch at full travel for approximately 2 seconds (or longer), then running to the opposite limit, holding for about 2 seconds (or longer). It is not unusual to have to do this after the battery is disconnected. The positioning of many of these features is controlled by a Hall's Effect generator, a simple device that counts revolutions of a motor shaft, and it must be set to register the proper number of turns to reach both limits of travel.

    Synchronizing Head Restraints:

    If the power supply was interrupted (battery disconnected or empty), the head restraints are no longer adjusted automatically. To resynchronize the adjustment feature, turn electronic key in steering lock to position 2, move the seat completely forward and the head restraint fully down, and hold respective buttons for approximately two seconds.

    Synchronizing power windows:

    If the power supply was interrupted (battery disconnected or low), the windows cannot be opened or closed by the Express feature. To resynchronize the express feature, press side of power window switch to resistance point until the window is completely closed and hold for additional 2 seconds. Repeat procedure for each window. The automatic full opening and closing procedure of the windows should now be restored. (Note: This sometimes works as well for problems with manual operation of the windows, but not always).

    Synchronizing sliding/pop-up roof:

    If the power supply was interrupted (battery disconnected or low), or if the sliding/pop-up roof is blocked during closing/opening procedure, the system has to be synchronized. To do so, turn electronic key in steering lock to position 2, move and hold switch in direction (3), until the sliding/pop-up roof is completely raised at rear, and hold for additional 1 second. If the pop-up roof simply will not open or close all the way after using this procedure, clean the tracks and lubricate them with the MB lubricant made for the purpose.

    Global Synchronization of auto open/unlock (windows open/close when car is unlocked/locked):

    Global synchronization synchs all of your windows and sunroof so that they all open or close by a single command (pointing the key at the IR receiver in the driver's door handle, and pushing & holding lock or unlock). Place the A/C switch on the A/C control panel in Auto, and the recirc button on. Then press the button between the temp controls and hold it until all of the windows and roof close. This should resynch them. After that, the Smart Key should open or close the windows and sunroof as well as lock or unlock the doors.

    Also: Door locks are controlled from the key by radio frequency, and will operate regardless of direction the key is pointed. The auto window/sunroof features are infrared, however, and operate only if the key is pointed at the small square IR receiver in the driver's door handle. The IR range is usually less than the RF range, and can be affected by bright sunlight directly on the door handle.

    Synchronizing ESP (ECU):

    If the power supply was interrupted (battery disconnected or empty), the BAS/ESP malfunction indicator lamp may be illuminated with the engine running. Turn steering wheel completely to the left and then to the right. The BAS/ESP malfunction indicator lamp should go out. For more on resetting the entire ECU, see

    Synchronizing remote control:

    The remote control may have to be resynchronized, if the vehicle cannot be locked or unlocked. To synchronize insert electronic key in steering lock. The remote control should once again be operational."

    Synchronizing Steering Column Height/Easy Exit:

    Steering wheel height - basically the same procedure, but with a caution. Move your steering column down SLIGHTLY, and if you can then bring it back up to where it started (but not higher), then you need to reset the column with the simple procedure below. HOWEVER, if it goes down slightly, but will not go back up at all, do not try the reset - it probably will go fully down and not come back up! You may not be able to get into the car to drive, if that happens. Get it serviced.

    Run the steering column full down, and holding the switch down for about 10 seconds after it reaches the lowest position; then run it back up fully and hold the switch up for about 10 seconds after the column reaches its upper limit of travel. You may need to do this several times. That should reset the limits in the Halls' Effect generator, and your column should function normally.

    Seats (easy exit) - try running them to the limits also; however, the seats slide back in the easy exit mode only if they are pretty far forward in the first place. if they are back beyond certain limits (set by Mercedes), not sliding further back is normal operation.

    Not all cars have easy exit feature, and those that do must have the option selected in the MFD (instrument cluster) menu.

    Resetting Automatic Windshield Wiper Function

    First, pull and reseat your windshield wiper relays (locations are on the fuse diagram usually found in the tool compartment in your spare tire well).

    With engine running and all passenger doors closed, starting at 0 turn on wipers to #3 position, then put the switch in the 0 position then put it in the auto #1 (rain sensor position) then have someone splash water on the windshield as the doors have to be closed to reset this function. Then they should function normally.

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