2000 s500..car wont start...key does nothing

[nuthead]

Battery is fully charged, all lights and powered options come on or working but the automatic start function doesnt engage.....not getting any response. car is of course locked in park so the steering wheel/transmission lock is fully engaged also. What do I do?

[79Mercy]

it probably needs a starter motor. youll need to get under the car and check for 12v volts with the key in the starter position at the small wire at the starter. if you have voltage when holding the key in the starter position you need to replace the starter motor.

[oldsinner111]

how about key battery?

[nuthead]

checked the key battery by locking and unlocking the doors....no problem.
if the battery were weak would it unlock the doors yet not have enough power to start the car?

[nuthead]

as I research more about the starter motor I came across a reference to the starter mootor getting water in it . It so happens that yesterday i got caught in a Florida afternoon rainstorm and ran through some very deep water. Although I finished my errand and the car restarted and came home this next time ive tried to start it the problem has occurred. Does this help with your diagnosis?

[mpolli]

Just FYI to anyone else reading this, the key battery (coin cell in the key) is not necessary to start the car. It is for the remote functions. The key has a passive RF chip for the start function.

[92300SE]

Do you hear a click when you insert the key in the slot?,if not,your smart key is dead,batteries in the fob have nothing to do with the smart key actual function...dealer will overnight you one from Germany,already programmed...their cost is about 140$,retail around 300$,that was last year...

[nuthead]

Ive owned this car for 1 year and have owned 2 other W220's and honestly don't remember any "click"....funny how you get used to something and it so routine that it could be missing and I would not know it. When I put the smartkey in, it turns easily all of the "accessory" functions (radio, dash lights, a/c blower etc) come on it's just doesnt kick into the start function. As I said before if it matters it is not unlocking the steering wheel or transmission.
Before I call a wrecker and have the thing drug up onto a flat bed in the morning some one please tell me if its the starter motor, the smartkey or a operator failure...lol

[engatwork]

Can you turn key at all? I had one in one time that the eis had gone bad. Car had to be flat bedded to the dealer. I did disassemble the center console enough to put it in neutral though.

Have you tried another key?

[nuthead]

I bought this car used with only one key. The key turns easily and springs back just like it should after i turn it far enough to initiate the start sequence just NOTHING happens.
I am disabled with Parkinsons and have to depend on others for help...either friends or the local tech. We did remove the battery first thing and took it to make sure it was producing enough cranking power....chart said it needed 760 amps to crank battery shows its producing 840. I thought maybe reconnecting the battery would cause some sort of computer reset but there was no difference. Thanks to all for your help.

[79Mercy]

did you check for power at starter with key in starting position?

[nuthead]

NO Im not able to do that myself thats why I was going to have to have the car towed to the tech for them to try your recomendation. Then someone brought up the issue of the smart key being dead and if its that simple I dont want to have the car towed only to find out that the local tech cant help..It seems to me that if the key does everything but iniate the start sequence that the key is OK and your original diagnosis is right

[92300SE]

If you turn the key,you have a good key,a bad transponder will not let you turn the key.There is no shift lock override on this model,at the shop,when they need to move a car with a missing key they tap several time the shifter in order to get it out of P to N,its all electric.Check your relays,you might have a disabled starter relay,

[nuthead]

Well guys 24 hours have passed and the situation has changed 180 degrees. Called to have the car flat bedded to the tech but faced with the problem if the car being in park I decided to take one of the bits of knowledge you guys imparted to tap on the shift lever to see if i could get it out of PARK. Before I got that point I of course put the smartkey in the ignition thinking it needed to at least be on to get the shift lever to work. THE CAR STARTED just like nothing had ever been wrong. Thats the good news, now the car is throwing 3 malfunction messages...ABS...ESP...BRAKING ASSIST?
What has happened now?

[Zulfiqar]

That model of car has one additional system to start the car. The shift lever also holds a chip that relays driver authentication. (E and C class cars dont have that)

If the lever was doused with liquid at some point (spilled water/coke/coffee) - it may compromise the car from being started. The 3 errors you see may also be related to it.

However there is one more possibility that your receptacle for the key is bad.