Rolandesq

PLEASE HELP!! Here are my symptoms in detail: All problems came on suddenly and everything worked fine up until this point. No unusual weather events (cold, rain, heat) preceded the problems. Opened car with key, put key in ignition to start, engine cranked but would not run. Turned off and tried again, same result. After a third try, engine won't even crank. Only a single click from center rear of engine (higher than the CPS location) and a single click from under rear passenger seat (assume this is fuel pump relay).

Now keys will not lock or unlock doors. However, locks work fine with inside switch so problem is not locking vacuum. Key turns in ignition and all electronic functions (radio, dash, lights, etc.) work fine. Battery has been tested and all is OK there. Batteries in keys have been replaced. All fuses and relays in all three fuseboxes have been tested and all are operating properly. If the battery is disconnected and reconnected, the engine will again crank for two or three separate tries and then returns to the single click scenario as above.

No error messages are displayed whatsoever. It seems to me that replacing the CSP is not going to be the solution as that doesn't have anything to do with the remote key system. I am hoping it isn't the EIS and it seems odd that the key would still turn in the ignition and crank two or three times reliably upon 'reset' by disconnecting the battery. It also seems odd that the keys (i have two and both produce the exact same result) are not recognized by the IR or the RF but will still turn in the ignition. I am a little confused as to whether or how the EIS plays a role in the remote key door lock system unless it is integrated with the IR and RF. I can't find a thread that discusses any such interaction.

Any and all ideas, leads, links and/or suggestions, with the exception of "take it to the stealership", are most graciously welcomed! I have scoured the threads on this and other sites, tried all suggestions I could find and am unable to find a solution that works or even alters the above symptoms. If anyone has a reliable, or even a semi-reliable, method to check whether it might be the EIS before I spend a couple thousand will be my hero and I will be forever in your debt! THANKS!

tusabes

Dude you have a weak battery. Change it and all will be well

MB-Dude

I agree... sounds like a weak battery. Only thing that ties it all together.
Cheers,
Jeff

tusabes

And just to be clear, I did see in your post that you checked the battery.

But w220 has an electrical system that is very finicky and even a battery that checks out good may be too weak for the w220 to work properly.

Walmart usually has the cheapest MB sized batteries. Autozone too. And You can probably return it, if it doesnt solve your problem.

If you want an official MB battery, MB roadside should be able to change the battery with an official MB battery and no install cost. Well at least they used to before the Roadside program was changed earlier this year. Worth a call to ask, and to see if theres any charge if the battery replacement does not fix the issue. But I think it will

Rolandesq

Thank you for your thoughts. I replaced the battery about a year ago when I ran into the slow drain/weak battery issue and Autozone swapped it out with no problem. I haven't experienced any problems since, until now. My current symptoms are very different than before.

For clarification, when I say the engine cranks following battery disconnect-reconnect, it is not like my prior weak battery experiences where the engine feels like it wants to start, but just can't. Here, the engine DOES turn over immediately when the key is turned, but just as quickly cuts off. The starter clearly starts the engine. The vehicle will not allow continued cranking once the engine starts. It will allow me to repeat this procedure two or three times, and then simply reverts to the single clicking until I 'reset' the battery again.

I am going to investigate the battery issue once again just to be sure since it is a helluva lot cheaper than a tow and diagnostic guesswork at the dealer. If that doesn't work, I think I'll push the car around the side of the house and into the lake in the backyard to start my own artificial reef!

jackasswhy

I had a similar problem but the key did not turn at all amd the key was the prob I could still do everything but.start

Rolandesq

Ok. Found some additional interesting information at crossfireforum.org.

http://www.crossfireforum.org/forum/...off-stuck.html permalinks #14 & 16.

I tested my car and found the scenario to be identical. After battery disconnect-reconnect the engine gives me EXACTLY three tries to start - and when it doesn't it kills itself. The link above indicates something called a SKREEM was the culprit. The crossfire forum contributor makes reference back to this forum, but I can't seem to find anything in this forum suggesting the W220 has a SKREEM, or even what it is exactly. Anybody heard of this? Is this the crossfire equivalent of the EIS?

MB-Dude

SKREEM is an acronym for Sentry Key Remote Electronic Entry Module. Not sure if there is a MB equivalent, though the Crossfire was one of the projects jointly done by the dubious Chrysler-Mercedes merger.

That said, I do not know of another, separate 'battery' for the MB entry system. Other than the main vehicle battery and the key fob batteries, the only other ones that come to mind are the TPMS for the tires (which is unrelated to this problem).

Try changing the battery in the key fob. Occasionally key fob batteries have been known to cause strange things. Maybe... just maybe, there is enough juice in the key fob to start cranking the car, but not enough to maintain the IR connection in the ignition switch. Do you have keyless ignition? If so, does it work? It shouldn't if the key fob battery is weak. Even with the new data presented, I still lean towards either the main vehicle battery or the key fob battery. Then again, stranger things have occured in MB's.

Cheers,
Jeff

Rolandesq

I checked the battery again and it was a little low on the amps (probably from my repeated start efforts and being parked without running for four days), voltage was perfect. Had the battery fully charged. Key fob batteries were also replaced. Crossed my fingers and tried to start the car again. Nothing. Same symptoms. Key fob won't lock/unlock doors. Allows me three tries and then shuts itself down. All other electronics are fine. UGH! For over 20 years I have always been able to DIY all my own automotive problems - I currently have an '02 Inifiniti QX4 and an '01 BMW Z3 and have been able to fix any and all weird issues that have arisen. Mercedes engineers, I applaude you for making a vehicle impossible to steal, and at the same time impossible to fix without paying your company even more. I feel like I am being taken by one of those computer viruses that show up with promises of the 'antidote' for a fee from the company that put it there! Grr....

MBtech1098

A Mercedes equivalent is DAS (Drive Authorization System). It is not a single control unit however.

Regarding the batteries in the smartkey, they have nothing to do with starting the vehicle. The EIS powers up the smartkey via a coil which induces voltage into the key. The batteries are only for RF and IR (in the door handle)

You will need to check DTC's one way or another. I may have missed in your post, but have you tried a spare key if available? If the same result you may have an EIS issue. All requests sent via the key (start, RF or IR function,etc) must be verified via the EIS.

Your issue is fairly easy to diagnose IF you have the right tool(SDS) and knowledge.

Rolandesq

All signs do point to the EIS. As an avid all-things-DIY'er, I know it always comes down to the right tool for the job. I had a similar type ignition/key non-recognition issue with my Inifiniti and was able to repair that myself since the codes are accessible without any tools, taking the vehicle to the dealer only for key reprogramming purposes. Alas, the star diagnosis tool is just too expensive for my home garage. I'll have it towed this week to the dealer. I'll post the actual problem once it is fixed with the cost of repair to enlighten others faced with the same dillemma.

S600Keith

All the members will really appreciate this. Please do follow up on this promise.

Rolandesq

Here is an excellent must read article for all mercedes owners explaining how the IR, RF, EIS, SAM, CAN and DCM all work together to control the door locks and ignition:

http://www.moderntiredealer.com/Arti...ace-to-go.aspx

Rolandesq

Final result: As I had thought, the problem was the electronic ignition switch. Total dealer cost to replace, including parts and labor, $988.50 plus tax. (@ MB of South Orlando)

In the end you might be able to buy the ignition switch (# 220-545-09-08) for about $400-$500 dollars online. I was too afraid of messing something else up with the other electronics and chose not to undertake the project myself. These theft avoidance devices are complicated for a reason! I was also told by the dealer that the part is VIN coded.

S600Keith

I would have probably bit the bullet on that one and taken it to the dealer also. It is well documented that messing with one part of the electronics can open a very large can of worms. I think $1K may have been excessive but it could have gotten a whole lot worse. I'm sure it just feels good to have the problems behind you. Good luck with the car.