Hey folks, first post for me here, and I'm looking for some advice on this peculiar keyless go problem.

I picked up a very clean, well documented 2011 S212 about 8 weeks ago. Very clean car, no accident damage, just some expected issues with the front spoiler meeting parking curbs with a well documented service history -- except for one issue that is the subject. 78k miles and just needed some tires, the sunroof frame tightened back up, and the subject of the day. Absolutely gorgeous in Capri Blue and nearly every option other than the rear seat video displays.

On the Keyless Go issues, the symptoms:

Generally speaking, the Keyless Go system frequently will not unlock the car or allow it to start and is exhibiting other symptoms as well. This is generally at first use after the vehicle has been sitting overnight, but on one occasion the issue appeared at 70 mph while the vehicle had been running for 90 minutes, and on another it occurred the evening of the last service I had at MB Manhattan after I had picked up the car and it sat for a few hours. Just to make it more interesting, it often occurs every day, but it will sometimes skip a day or two and it’s also gone for 10 days without any symptoms, only to return. Clearing the problem so the car will function for the rest of the day usually requires turning the ignition on and off, then opening and closing the driver’s door once you’ve gained access to the interior with the “hard key” in the key fob. Batteries in both key fobs have been replaced several times in the 8 weeks I’ve owned the car with no effect on the problem. There is one old code set in the module, but this may or may not be related to the current problem, as it relates to a power issue that could have appeared when I disconnected the battery to work on something else in the car.

Documented Keyless Go symptoms include:

• Does not unlock car with door handle or key fob buttons (obviously common)
• Unlocks car, but then won’t recognize that the key is in the vehicle and won’t allow the car to start (also not uncommon)
• Turns on the COMAND system display, radio, and other functions related to the COMAND system without unlocking the door (it shouldn’t turn this on ever). COMAND turns back off as soon as you open the driver’s door from the outside with the hard key – as if I was exiting the vehicle instead of entering it. (quite uncommon)
• Will unlock and open the rear cargo door without allowing you to unlock the rest of the vehicle after many attempts with the door handle or key fob buttons while still allowing the tailgate to operate normally.·
• Allows you in the car with either the door handle or key fob, but may or may not allow the car to start with either the push button or inserting the key fob.·
• Allows you in the car with either the door handle or key AND allows the car to start, but will not select any gear for the transmission. Remains in Park.·
• Decides key is not in the car after 90 minutes of Interstate 95 driving, forcing me to pull off the road to reset the system by turning the car off, opening and closing the driver’s door, and then restarting the car.·
• Several combinations of these symptoms have been seen (e.g. unlocks car, turns on radio, but then won’t go into gear once started).

Given these symptoms, particularly the radio-related ones, I suspect the Keyless Go module itself is at fault and needs to be replaced. Clearly the key fob batteries aren’t the issue, and probably not the antennas either, as it works just fine after resetting it. The dealer service rep at MB Manhattan “said” they reflashed the module, but there was nothing on the ticket – just another key fob battery change, and I suspect that’s all they did as I wasn’t charged for it, a module reflash was not indicated on the ticket, and the symptoms reappeared on the very same evening after the service – despite having given them a blank check to fix it.

Any thoughts?

Mark

 

I think you may know more than the dealer does!

 

I have had similar issues with my 2014 E350. It happens a few times a week and only in the morning after the car has been sitting. They replaced batteries 4 or 5 times and eventually replaced one of the keys. The problem has persisted. My car is going in for faded trim replacement and thanks to your post- I'm having them check this again.

 

Speak with Service Manager, present copies of attached bulletins. If VIN and/or part #s documented are applicable to your vehicle request MB goodwill repair given known production defects.

 

Konigstiger- Thanks for the info. I read the bulletins but it appears my issue is not consistent with those symptoms.

 

Does it happen with both fobs or just one? Can you narrow it down to just one fob?

Maybe you should go back and have them update the firmware again. Last time I was there, I had them update the firmware for bluetooth, Sirius and keyless go. They needed a reason so I told them that bluetooth and Sirius cut out once in a while. You do have an existing complaint so maybe whoever did it last time skipped the update as it doesn't seem to be in your paperwork. You could go there and ask for a master tech to do the work.

Don't forget the $150 off $300 good til Dec 31st.

https://www.mbusa.com/mercedes/servi...n_back_savings

 

Sadly, neither of these applies for me, but this is good to know.

 

Both keys, one of which is brand new.

I might give that a try and see what happens. I have an appt tomorrow with an indy shop with the STAR system to take a look and I thought I'd give that route a try first. I'd rather have someone go fishing at an independent's labor rate than MB Manhattan's. Also, given that the alarm siren is inop as well and the car was maintained on schedule at MB Manhattan (same dealer), I'm strongly suspecting they've seen this problem on this particular car before and the original owner didn't choose to fix it -- rather just yanked (and lost) the start button and the fuse for the alarm.

 

BTW, out of curiosity, if this thing decides the key isn't in the car at 70mph again, is it going to shut off at some point, or can I safely ignore it?

 

About the symptoms, yes. About the cure, I hope not...

 

Well I think asking for a master tech might be the way to go. I never got a good answer as to whether a knock off star system can do system firmware updates or not. It's the only real reason left to use the dealer. Also I assume your phone isn't anywhere near the key, that also tends to block the signal.

You might also want to get yourself a cheap scanner too. Here's one for $79:

 

Of course the cell phone is nearby. However, I don't usually keep both in the same pocket. Don't want to scratch up my phone.

You know, I keep hearing this on this forum, but it's not generally true.. FWIW, I'm an RF engineer for a supplier to the cell phone carriers. The key operates at 315MHz, the cell phone between 735 MHz and 2.1 GHz and both are pretty low power devices. Though the key is decidedly lower power, the frequency it operates at has a much longer natural range, unlike a cell phone's frequency at the same power level. That said, that's some pretty awful RF receiver filtering on the module if it's being overwhelmed by the phone simply being somewhere on my body or in the car. FCC wouldn't have type accepted it and you couldn't use it in the US if that were the case (they regulate how much power the transmitter can have, what frequency it can operate at, and how much of the signal can spread outside of the intended frequency among other things).

A cell phone does not continuously transmit. If it's not actively sending data during a call or large file transfer, it sends very short "keep-alive" messages periodically so that the tower knows it's there -- otherwise it's just listening, which is why the cell phone battery can last for days on standby while only hours when you're actually talking on it. The odds of both devices transmitting at the same time while you're not talking on it are very very low. If you're experiencing this yourself, then you might want to invest in the Powerball, as you are certainly beating the odds by a large margin.

For this to be true (and it is at least possible while not likely), one would have to have the key right on the phone during an active phone call with the phone compensating with max transmit power for a weak tower signal for this to make any appreciable difference, and even then it's a matter of how far away from the car (receiver) you are. Inside the car isn't far enough away for this to be anything other than an excuse by the dealer (or the manufacturer) for not having fixed something they can't figure out when the vehicle comes in for repair.

I get into between 50-60 different rental cars every year as a result of business travel, most of which have keyless entry systems that never exhibit this symptom regardless of what pocket my phone is in. I doubt that whatever radio manufacturer Benz is using here would support that interference statement, though it has a certain "truthiness" about it to give to the non-RF Engineer as an excuse to escape responsibility. Wouldn't at all surprise me if this rumor started with a MB service advisor somewhere making up a story to escape a high dollar customer's dissatisfaction for a failure of the technician to reproduce a problem.

BTW, while I have a generic OBD II scanner, I'm open to code scanner recommendations for this car. I've been looking at the iCarsoft MB II v2.0 as sort of a mid-range diag tool. There's a $1800 Autel unit that I'd really like to have, but just can't see spending that kind of dough for something I hope to use infrequently.

 

Well it happens to me. Typically the phone is right next to the fob in my pocket so the car doesn't recognize the key. Basically it's not so much the frequencies interfering with each other than the phone basically blocking the signal, an attenuation of the signal. Also happens when people leave the key in the car and the phone is sitting on top, sometimes the car won't recognize that the key is in the car and will lock the doors which it isn't supposed to do.

 

A more reasonable explanation. There's a lot of metal in a phone. Guess I've never left my phone sitting on top of my car keys before, so I just tried to do this.

14 yards was the tipping point where the key wasn't able to lock or unlock the car when the phone was between the car and the key, and I was holding the key to the phone with the phone between it and the car. Tried an ungrounded thin metal box and I got to 16 yards before it degraded the key signal enough that it didn't work. That said, it was much thinner than the phone and certainly wasn't emitting any EM radiation raising the RF noise floor.

But inside or anywhere in close proximity to the car? I'm pretty skeptical that it's the phone. That's likely an indicator for a new battery, which doesn't disprove either your point or mine, but does indicate the cause. It shouldn't do that.

BTW, you're probably aware, but you know you can nearly triple the range of your key fob by holding it against your jaw, opening your mouth, and facing the car? Your body becomes a wave guide, focusing some of the transit energy towards what you're looking at. Useful if you're trying to figure out where you left your car in the airport parking lot the week before....

 

Yes, I'm also an EE. Basically your body acts like an antenna.

I assume you mean you pressed the button from 14 yards away? I never use the buttons, that's what keyless go is for. But sometimes it's annoying when you're trying to get into the car and the unlock feature doesn't work, and once I move the phone out of the way or take the key out, then it works. But that sorta defeats the point of it sometimes, you're supposed to be able to just leave the keys in your pocket and go. It's possible that the car may also be asleep and trying the door handle wakes it up, I seem to recall that someone mentioned that it stops scanning after 3 days or so.

 

Yes, buttons, but it's transferable to the discussion at hand. Also, what you're talking about is keyless entry (opens the door), not keyless go (starts the car). In anycase, it's still 315MHz, and would necessarily have to be the same attenuation issue. Are you thinking that the fob transmits at a higher power when you press a button, or is it just sending a code at the same power level? (I recognize there have been several threads on this with mixed opinions expressed). It also strikes me that you could have door handle sensor issues. I've seen a couple threads on that as well.

Interesting discussion and I clearly don't have the facts regarding the radio and logic design here to call it one way or the other, but it's not really relevant to my current situation. The key fob doesn't normally have the ability to turn on the radio, not to mention doing that without letting you in the car to at least turn down the volume....

 

Actually keyless go is the ability to open and lock the doors without using the fob. As long as the fob is nearby, the sensors on the door will detect the fob and either unlock or lock the doors. Also works for the trunk and the gas cap. If you just have keyless entry which is just the fob, then you have to hit the buttons and there's no sensors on the door handles for entry or locking. They're better on the W212, in the W211, water would get inside the rubber membrane and rust out the contact switch, but the W212 does something else and at least it's sealed against the elements. Those keyless go door handles are way more than the regular handles.

I don't think it's a door handle issue as usually when you pull the door handle and it doesn't open, it still gives you a message on the dash that the key is not detected. When you take it out, it opens the door. Either the phone is blocking it or I'm reaching out and the fob still isn't close enough for the car to detect it, or just pulling the handle woke it up but not quickly enough to detect the key. You can also shut off the key by pressing the lock button on the fob twice. Sometimes the car sits for a week before I end up using it.

 

I have been really happy with the Chinese Launch Pro. You can see a picture of it in my thread here: https://mbworld.org/forums/e-class-w...or-0521-a.html

Here it is on Amazon:

Looks like it's gone up about $150 since I bought it a few months ago, but it's fantastic. It works with my BMW too. If you search around on Youtube, some vloggers have coupon codes so you might be able to get under $600.

 

This is the info I received from my Service Advisor today: "I will give you an update as to what we find. I do know that if you are locking the car with the key fob, it disables the keyless entry feature. I just want to make sure that you are locking the vehicle via keyless entry/exit."

I don't think this is correct. I have a habit of pressing the Lock Button on both My Fob and My Wifes ML Fob EVERY NIGHT before I go to sleep. I'm 99.9% sure the vehicles are locked, but I do it as an added assurance. I also press the Lock Button on the FOB as I am walking into work. If his info was correct- the Vehicle would NEVER unlock via KeylessGO 'Door HandleTouch'.

 

He's probably thinking that maybe you hit the button twice. If you hit the fob button twice, it disables keyless go on the fob. If you hit it just once, then it doesn't. I never hit the button. I just look at the door pins, they normally move down and the car makes a noise so I know the car is locked.

 

Sounds like made up horse poo to me.

 

Sounds like extemporaneous horse poo to me. No other car on the planet works like that.

 

Well...The SA was partially correct. Like cetialpha5 stated above- I was most likely pressing the Lock button twice which would deactivate the KeylessGO 'Unlock By Touch' option. My habit at bedtime was to pick up my keys and press the Lock button rapidly a few times to assure that the vehicle was locked. I was not aware that this button pushing would cause this. It's good to know because I drove me insane when I was wiping my car and the towels touched the door handle and the vehicle would honk and lock the doors. I can now disable the 'Touch Option' when detailing my car.

 

I have the Easydiag Plus 2.0 version which just does diagnostic but doesn't have the ability to make changes or customizations. They have a 3.0 version now that's in the $150-$200 range, the prices keep going up. When I got mine, it was only $30 a few years ago. For $600+, I'd probably prefer a Star Xentry knock off system which is in the same price range although I can see how it's basically half price if you use the system on 2 car lines.

As for the keyless go problem, hopefully that's the solution. This has been discussed in other threads where they talk about thieves stealing cars by using a range extended to steal the signal from the keyless go fob and then they just steal the car. The solution was to either shut the fob off by pressing it twice or by putting the fob in a faraday cage box. My car is out in a parking lot and I'm in a building complex so I'm not worried that people will be outside my door trying to steal the signal. Plus there are nicer cars in the lot to steal and if they do steal it, that's what insurance is for.

 

Ok, still fighting with this 6 months later. Car has been at MB Manhattan (MB Factory Store) for this 10 times now and they are still scratching their heads. The independent shop I was using threw in the towel after a few weeks of getting nowhere. Dealer replaced the front KG antenna (throwing codes) and Central Gateway (not throwing codes itself, but the devices connected to it complain about "implausible data" in their own codes). No effect. Notably, the KG never throws a code, but it is always affected. The other symptoms either appear or not, seemingly dependent only on the mood of the car at the time and even the KG symptoms themselves can vary.

Key fobs aren't the issue. They can't turn on the radio or wipers. Doesn't matter if they are sense-able by the vehicle or not, the symptoms will still present themselves without the key in range of the car (wipers go to top of stroke over night with the car a block away and the key behind a 2' thick stone wall). Also doesn't matter if I try to open it with the door handle or the key fob buttons. My phone is also no where near the key when I attempt to open it. Dealer also pulled all the carpets to check for any water leaks or signs of flood damage. No evidence of water found.

I've been taking videos lately for the dealer, because of course it never occurs when they have it, though I've been dropping it off every Monday and picking it up every Friday for the last 8 weeks (10 visits for this complaint in total). They are here: https://www.dropbox.com/sh/yl7ud94oc...1MVVWU4na?dl=0. If you watch a few of these, you'll see the variation in the symptoms and probably laugh at its antics. I'm not finding it so amusing myself anymore, but I certainly can see the humor in it.

Symptoms include:

• · Does not unlock car with door handle or key fob buttons
• · Unlocks car, but then won’t recognize that the key is in the vehicle and won’t allow the car to start
• · Turns on the COMAND system display and other functions related to the COMAND screen and audio without unlocking the door (it shouldn’t turn this on ever). COMAND turns back off as soon as you open the driver’s door from the outside with the hard key – as if I was exiting the vehicle instead of entering it.
• · Unlocks and opens the rear cargo door without allowing you to unlock the rest of the vehicle after many attempts with the door handle or key fob buttons while still allowing the tailgate to operate normally.
• · Allows you in the car with either the door handle or key fob, but may or may not allow the car to start with either the push button or inserting the key fob.
• · Allows you in the car with either the door handle or key AND allows the car to start, but will not select any gear for the transmission. Remains in Park.
• · Decides key is not in the car after 90 minutes of Interstate 95 driving, forcing me to pull off the road to reset the system by turning the car off, opening and closing the driver’s door, and then restarting the car (only happened once).
• · Several combinations of these symptoms have been seen (e.g. unlocks car, turns on radio, but then won’t go into gear once started).
• · If the switch for the rain-sensing wipers is left in the 1st or 2nd intermittent position over night, and if the Keyless Go symptoms occur, then the wipers will be parked at the top of their stroke when I come out to the car as if I had shut the car off before the wipers finished their stroke.

CG and front KG antenna have already been replaced. If anyone has some thoughts on what to try next, I'm interested in hearing them. Though there are no codes for it present, I'm probably going to have them swap out the KG module as I've already come to the conclusion we're going to have to replace some otherwise perfectly functioning parts just to find the problem, but there's a lot of expensive, non-returnable stuff in there to try just throwing parts at it hoping to get lucky.