ey3sburn

hello, searched forums a lot but did not find situation that fits mine, as in my case it wont lock/unlock and wont turn in ignition. key batteris are okay( even tho it is not needed to start vehicle), car battery is good(lights/beams work) when i insert key in ignition there is no sound ( swish sound when steering lock is released) steps i tried : disconnected battery for about 30 min, checked all fuses. . obviously i dont have a spare key to check if key is defective.
from what i gathered, it might be either key or EIS (electronic ignition switch) which fails sometimes, even tho i did not jump started car nor did something special, just turned off car after normal driving. one thing, after i turned off car, i leaved key in 0 postion for some time, may be half hour max, i dont really remember but when i removed key from ignition there was not swoosh sound, but i might be wrong.
so there are two options, key or eis, or is it something else i should check? and in case EIS is defective, should i buy only eis module or eis, key and ecu all togahther? hope someone helps. thanks!

Serndipity

Before you start throwing money at your problem, I thought it would be helpful to understand how the MB drive authorization system (i.e. DAS) operates.



Point being that your key fob, the EIS and ESL must all be in good working order and if replacement of any are required, the replacement part needs to be vehicle coded to your VIN.

But before you start throwing good money after bad to solve your issue, I have some suggestions.

Even though you said that you checked all your fuses, the only above module that requires 'always available 12 volt primary battery power' (e.g. circuit 30) , to the ESL module is fuse # 27 which is located in fuse box F1.

Did you use a multi-meter or test lamp to verify that 12 volts is present to the module? Note: sometimes the fuse contacts, when plugged into its socket, can be corroded as well (e.g. due to dissimulator metals, moisture etc.).

However, all that said, in the title of your post, you indicated that in addition to vehicle authorization, your key fob, additionally does not operate your central locking system, which is independent of DAS3, which suggests that it is defective, but unfortunately, you do not have a spare fob to verify.

In your case, the MB STAR diagnostics, should be able to diagnose where the fault lies.

However, beforehand, when the key fob fails, it's often because of a failed solder contact on it's internal printed circuit board, which in modern times became an issue, when they took the lead out of solder.

If you have a soldering iron, with a fine tip and steady hand, re-soldering the contacts may restore full functionally .

There are numerous YouTube videos that show how to remove the printed circuit board from the fob and it's components. In general, authorization failure is due to the induction coil or ROM chip contacts, while 100% failure may be caused by the microprocessor chip contacts.

AlinaR

Hi! Few years after we have the same issue. We do have and tried 2 keys and none works. Can you tell us how you solved the issue. Thnx