Alex3

Hello, Im new to the forum and I am stuck on wether my smart key or EIS is failing in my car. I know you can never be sure unless you have spare key or buy a new one, but any help would be greatly appreciated. I will try to be as detailed as possible in my symptom list.


I first noticed my key was not unlocking/locking the car doors after manually unlocking the doors I then put the key in the ignition which didn't make the routine click noise when inserted nor would move. the panic button also doesn't work.

After changing key batteries, checking infrared, cleaning infrared, and doing research 3 days have passed since the problem first occurred, and I then try to jump the battery, but before I can even fully unlatch the back seat to access the battery I try one last time, and the key locks/unlocks the door along as turns fine in the ignition. I also want to note when it did turn on there was an abs light that turned on that then went of when in drive, also I have a check engine light that has always been on that was no longer on. The check engine light eventually came back as it always as does when I clear codes with the machine (just to clear up any confusion I did not clear codes with the machine this time to get rid of check engine)

A day later of driving and shutting the car off and starting it back up around 6 pm I come out of the gas station to unlock my car and nothing, put the key in the ignition nothing, hit the alarm nothing. My windows where down so I rolled them up by putting my key in the driver side door and holding it in the lock position. Finally when I gave up and the tow driver came the driver then put my car on the lift and the alarm went off until I put the key in the door.

My question now is has anyone experienced the symptoms I have, and if so what was the diagnosis. Again any, and all help is appreciated.

Plutoe

The key batteries have nothing to do with starting the car!!

Because the EIS is a very expensive part, I would spend the upfront money and get a quick test at the dealer--- and remember the EIS is a theft relevant part that requires DAS Xentry to code sync bla bla to the car---therefore if your girlfriends brothers uncle says--Oh I can do that------just clap!!

Alex3

Hello, plutoe, and thanks for the timely response. I know the batteries have nothing to do with the ignition just was troubleshooting the key pads functionality, also I'm aware it is impossible for an Indy mechanic to fix the EIS. I guess what my real questions are when the EIS fails should it affect my lock/unlock on my key? and if so what are there relations to one another? also I found it odd that within the first 3 day strech of the key not working I must have tried the key 500 times and nothing, but in a last ditch effort I try one more time before trying a jump, and bam doors lock/unlock key turns fine no problem for 24 hours then again nothing. I Also saw you mentioned something about mercedes running a test? I called mercedes and they said I need a new key first before they can run a test, or are they just trying to get more money from me? And if so what is the test called?

Plutoe

No

See post 2 for test description

No you don't need a new key to run a quick test, however because the MB tester uses the vehicles battery voltage--the key must be able to move position within the EIS to the ON?OFF position!----will your key do that!!

Additionally the key has two functions--connivance functions and starting recognition

You never mentioned a spare key---do you have one

In the finally it is going to come down to either a bad key or bad ignition module--another key is way less expensive that an EIS!!

Alex3

Unfortunately I bought the car with no spare, and when I put the key in the ignition it doesn't make the routine click unlocking the wheel, also not allowing me to turn the key so it looks like a diagnostic machine is out of the question. Have you also had to deal with this problem as well?

Plutoe

Nope, I have DAS Xentry diagnostic machine, however I can't help people if the key will not turn---that's dealer time!--They have special keys(not for sale) to solve that problem

Alex3

Thanks for all your help, I'll be taking my car to the dealership Monday I'll make sure to post back with there findings.

raymond g-

i've not seen where you've verified full battery charge on the car yet. you may
want to do this first, since the auto electronics rely on a healthy battery. if
allowed to drop down to the threshold of no/go, various appliances on the car
will begin to act wonky and unpredictably.

if battery is avg flooded cell, verify proper specific gravity and fluid level. top
with distilled water, then trickle charge with 10 amp charger overnight. check
SG again, fluid level and repeat until vitals are stable and in the 13vdc range
immediately after charging

Alex3

Unfortunately I don't think it's the battery because the seats move, dome lights/ headlights work & windows roll up (when metal key is in drivers door turned in the lock position) unless there's something else that could be wrong with the battery, because I found it odd my check engine light was off when I turned the car back on when the light has never gone off by itself. Could something of reset itself in the car causing the key to temporary work?

raymond g-

well, I guess we have a different approach to troubleshooting. mine is more
from a perspective of eliminating the obvious. yours is to eliminate what you
believe should not be the cause...which, if incorrect, may leave open the
possibility that it could have causal effect.

Alex3

Hey, Raymond I can't really follow what your trying to tell me in your last post, however I mentioned all electronics work, but did leave out I have tryed jumping the battery anyways to no avail.

Alex3

Just got my car back from the dealer turn out to be just the key

bbirdwell

"I then try to jump the battery, but before I can even fully unlatch the back seat to access the battery "

You don't need to pull the rear seat out if you are only looking to jump the car or test battery voltage. There are +/- jumper connections under the hood in front of the SAM module.

Chris8

Alex3, so what was wrong with the key? I presume you had to replace it? If so, can you say how much it was?

bbirdwell

A replacement key for my W210 was $278. A replacement key for my W211 was $473. From the same dealer.


Next time I buy a Mercedes, if the seller doesn't have two keys, they are going to purchase a spare key out of their pocket before I buy the d--n car.

Alex3

The replacement cost was 225 with door key, however they originally wanted 285 after a bit of haggling they managed to lower it. Also Mercedes roadside assistance towed it for free because it was considered getting work done. I never was able to figured out what was wrong with the key though even after complete disassembly.