ereed

I am having a hell of a time getting my Keyless Go problem diagnosed. The system isn't throwing any recorded errors, the car battery and fob batteries are fine, so the dealer just shrugs at us. I thought I'd turn to you guys.

To sum up, all three of our key fobs "are not recognized" or just do nothing sporadically. Sometimes it works, sometimes it doesn't. We can't even use the valet key because it will set the alarm off. The only constant I can find is when the car is very cold (today was 25f deg), like when sitting in our driveway overnight, it just will not respond. All keys, all brought out one at a time (it reminds me of presenting offerings to the car begging it to like us). Today I waited for the sun to hit the car for awhile and bazinga! Car opens up. Car starts.

Thoughts? Help? Do any of you know what I can guide my mechanic to? Or should I just go somewhere else because I am feeling he is less a mechanic and more of a computer error responder. FWIW, the folks i use are Mercedes dealers.

Richard Arnold

We also have an increasing problem with our 2004 S600 'Keyless Go'. This year, in the cold weather only, it will not start the car. It will crank the engine for 2 seconds and then stops. No matter how many times we try, it won't start. However, it starts with the key, no problem. The problem started 4 years ago, but only happen once in awhile. It got worse each year. And its getting more sensitive each winter, even when the weather is not as cold as the previous winter.

The mechanics at the dealership, couldn't find the problem last winter, or the winter previously. However, they drove the car into the warm garage to inspect it each time. Its never been a problem in the warmth, so far. The mechanics haven't been particularly good on other problems either! So we having tried them this winter.

The battery is 6 years old, but has never failed us. But don't know if its a factor as it starts with the key.

Sorry that I'm no help, but if it I find something, I'll post an update.

AH1W-COBRA

the unit that stores user memory and has input on just about every gadget in the vehicle. im sure someone will correct me if the accronym isnt correct but our dealer went through hell trying to find gremlins that only came out to play on initial starts on cold mornings.once the vehicle was warmed for only a few minutes everything was perfect. it took them 8 days to finally get it fixed, it also through no codes. replaced the EIS and 100% repaired. they need all your fobs/keys to turn in with old unit for security.

Richard Arnold

I thought I would give the dealership one more try. I called and without seeing the car, they suggested that it may be a weak battery in the key fobe. I don't think that I'll waste my time with them.

There is a specialty Mercedes repair shop in our town. Good reputation. I'll try him and advise him what you found. Once we get the car back, I'll post the lastest news for you.

Taking 8 days to find the problem is scary. Thanks for the tip. It should shorten the time to check out the car.

AH1W-COBRA

we live in the high desert, cold mornings are 25 to 35 f. our dealer is sandiego and they could not get it to fail for the first few days and then finally they left the car outside and brought all the test equipment to the car instead of the car to the test equip. and sure enough on initial startup it diagnosed itself as eis with a single code. i dont understand why the code wasnt stored in memory.also i made a dvd at my home of the car when it was having the problem and this really helped the techs. i am a mech/tech and my own personal opinion is to try and find a different dealer, when it comes to electrical problems and they have to disassemble things like dashboard components, door panels, seats/carpet. ill opt for the certified MB mechs any day of the week. they dont destroy things when they r&r somthing and they arent guessing how somthing comes apart for the first time cause they have done it before. IMO

Richard Arnold

This is a little embassing, but the problem was simply the battery Keyless Go fob was the problem. The problem first surfaced when the car would not start without using the fob in the ignition (once in awhile during cold weather). The problem became more frequent until it would not start the car, unless the fob was in the ignition. Then suddenly last month, it would not start the car at all, even with the fob in the ignition. In desperation, as we needed the car, I got the spare fob out and tried starting the car with the fob in the ignition. It started OK! So I thought I would try to start it with the fob outside the ignition. Surprise! it worked fine starting the car. So off I went the next day to the dealership for a $15 battery. No problems since.

I do appreciate you all responding with your stories.

Jerry-

This thread has come to a shameful end. Firstly, the battery is a standard CR2025 and can be bought for under $5. Secondly, it insinuates that the battery in the fob has anything to do with starting the car with the key inserted. When inserted power is "Inducted" into the key from the car induction coil and it does not matter if the fob battery is full, empty or missing.

Thirdly, I have the same problem too on my 2004 S600. I always check the battery in the keyfob with a voltmeter and never find a problem there. I have two suspects: if the car has low battery voltage then it switches off all devices that are not essentail. Keyless go may be one of these. The other thought is that one of the fob buttons was pressed accidentally in my pocket and was less powerful at that moment.

Neither theory is confirmed.

Can you check the following and report back to me? When you touch the door handle, please look a the key. Does the LED light up as if you had pressed a button on the key? If the LED lights up on mine then all is well.

Richard Arnold

Thanks, for writing into MBWorld. It prompted me to test it again. I have only been using the other key fob with a relatively new battery.
The temperature has warmed up somewhat. Last night it was approximately 5 – 10 F. I tried the key fob with the old battery, pressed the driver’s door button, and the red light on the key fob lit up! I decided to try to start the car by pressing the button on the shifter, and the car started! I was so surprised that I didn’t bother to try the key fob in the ignition.
I can’t even guess at what was originally going on with the key fob. The other key fob with the new battery was left in the house away from the car. I suppose that it’s possible that the car battery was low, but with the really cold temperatures that we had previously, I would have suspected that the car wouldn’t start with either of the key fobs. But the car battery is 7 years old!
I’ll continue to use the key fob with the old battery and report on what happens next.
Richard Arnold

Richard Arnold

Just an update on my previous problems. The key fob has been working fine every time, except on 2 occassions. In both cases, the key fob was able to start 'cranking' the engine, but the engine stopped cranking very quicking. Then the key fob was used to reset the dash, and then it started the engine on the next try.

As I mentioned in an earlier posting, this problem used to be a winter issue that got worse each year. Its confusing to understand how the batteries could be an increasing problem each winter, but take so many years without the battery being completely 'dead'.

Richard Arnold

04S600AMG

I realize I'm coming back to this thread a few years late however I noticed the original poster, ereed, never came back with what fixed his issue. I am having the exact same issue. I am pretty sure based on all that I have read that my problem is with the EIS however I have a few concerns that maybe somebody out there can help me with. Oh and by the way, I have already called the dealership and asked them these questions and they all but hung up on me. I notice on ebay there are several used W220 Keyless Go (EIS/Shifter/Control Module) setups for sale. Most come with one key. My question's are, can I retrofit one of these into my car and have it work? If it will, do I have to still have the dealer do something with Star Diagnostics? If it won't, why not? If I purchase a new EIS does it include new keys? If not, will I have to buy new keys or can it use/reprogram my old keys for the new EIS? Thanks guys. I would be forever grateful for the answers.