It's likely gone bad, it's not a dead key battery issue. Try the spare key
and see if it starts & runs. If so, then it's the key for sure.
This is the infamous "Voice of experience" speaking ;-) One of MB's
illustrious dealers here in the USA managed to break my '00 E430 Sport's key
after I'd driven the car over 200mi to them to get it serviced (no local
dealer). They then tried to disavow any responsibility, etc., etc.
(naturally). Having neglected to pack the little spare key, I was facing a
400 mile trip to home & back just over the stupid key. I looked at it and
found they'd broken off the little clear red plastic tip on the thing. I
found it on the floor near the service advisors desk, put it back on with
some superglue (which they were reluctant to supply) banged it on his desk a
few times and it worked. It then took them over three months to get me a
replacement key ....so goes my MB "Experience"!
Look at the very end of the key unit, if the tip is badly scratched or
broken it may have an effect. Also, try just banging it on something to see
if it starts working again. Should be a warranty item if it has actually
On Sun, 26 Oct 2003 17:10:12 -0700, "Gerald G. McGeorge"
Erm, no it doesn't.
The drive authorisation process is as such:
Transponder in key is energised by RF transmission from EIS, this then
powers the key to transmit its drive authorisation signal via the IR
port (The batteries in your key are purely for locking/unlocking the
vehicle, try dropping the batteries out of your key and see if you can
still start the car). This signal is then passed via the EIS to the
electronic steering lock, if the steering lock is happy with the
information sent by the key (i.e. if it is the right key for the car)
it will detach the steering lock and then send a signal back to the
EIS switch informing that this has been done. The EIS will now allow
the key to turn for cranking and will then send the drive
authorisation signal to the engine control unit where it will again be
checked and if it is correct the car will crank and run.
There are no conditions as you describe where the car will crank but
not run due to key logic and if you understood the workings of the
drive authorisation system you would see why this is not possible.
Each component processes they key's signal and if it is happy with it
then it will all work, if it isn't happy with it then you won't even
get the steering lock off or be able to turn the key, you certainly
won't be cranking the engine!
In my case the broken key would unlock the column and the engine would crank
and fire, but it would not stay running. It would rev to about 1000 rpm and
die. After we repaired the little red end piece and banged on it it stayed
working until the dealer was done with the servicing and I got it home.
Thanks everyone for the help.
It has not happened again and I am carrying my spare key and will see what
Maybe it was just a fluke and won't happen again.
The dealer said that it was not likely that there is a sevice coded stored.
I will let you all know if I find out something.
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