Hey there. Car is 2011 W221. Is there a way to disable the annoying "replace key battery message" using STAR? I know I need to replace the battery, because the key fob stops working SIX MONTHS after the message appears. I would highly appreciate it if I'm able to make use of a battery for more than a week without being nagged.

Thanks for any info!

 

I'm pretty sure it can be coded out but not 100% on that.

Maybe get a new fob and see if it changes? Does it do this with both key fobs

 

I'm not sure how long I have between the message and key not working, my issue was the short time between a new batt and the message. The alert appears at 3.06V and new batts are often already close to that. So I charge them to ~3.45V and problem solved. Plus you can recharge the existing batt when it eventually runs low so, over and over, so if you really want to squeeze use out of the batt, this is the way.
I also modded the key to accept the longer lasting and much easier to find 2032 batts.

I used to use a home made charger but I saw this one online that works pretty good. It only goes to 3.35v but close enough.

https://aliexpress.us/item/3256806755446134.html

 

Yes, it can be turned off in STAR. It's in the key/remote settings. Any decent independent specialist with STAR can do it in a few minutes. Just tell them to disable the key battery warning message.

 

Thanks guys, I'll get it coded out on my next visit to the hackerman.

I thought the chemistry in these batteries is non-reversible? I ordered one of those chargers, let's see how it goes. It will only make a small pop at most, anyways :-)

How did you do that without compromising the rubber seal? Is it just the plastic case that needs grinding down to allow for a thicker battery?

I always thought it funny that this key is bigger, has keyless go, and yet uses a single battery vs the former's 2x2025.

How did you make it, is it simple enough? Might do it if I have some spare time and the cheap one annoys me.

 

They don't want you to recharge, that would cut into profits.
You can recharge just about any battery, but how well they take it varies. The 2032 batts take it rather well. Typical Duracell AA etc not so much, but well enough that the first charge is usually very good, then less so for each charge after. I usually recharge them at least once, but often two, sometimes three times, but usually toss them after that. A drawback is they sometimes fail during charge, or during use. Not often, but it happens. I'm usually not trying to squeeze the max from a batt, just compensate for what seems excessive cost.

A typical AA etc also work well enough that I stopped using typical NiMH rechargeable AA because the only drawback is the # of charges they can take, otherwise a normal NiMH batt sucks. Plus NiMH never last anywhere near the claimed 1000 charges, but their voltage is so low they're just about useless anyway. I have tried AA Lithium, both limited to 1.5v and 3.6v. The 1.5 almost set my place on fire, the 3.6 are nice but they simply didn't have the ampacity to make it worth two AA, but I'm hopeful they will improve and replace Alkaline.

I have had actual rechargeable 2032 batts, until I realized they were no better than the normal 2032. Imo the only difference was the word "Rechargeable" on the battery.

The charger I made was simply a 2032 holder meant for a computer, then I fed it 5V from USB using a resistor to limit current. They don't care for much current so I was limiting it to 20mA. I probably should've used 10 or 5mA but it worked.
I simply checked voltage now and then until it hits ~3.45 and call it good. I could go higher but my worry is not the batt, it's the key, which is very expensive so I'm unwilling to find what voltage is too much.

The charger I bought, which I assume will be exactly what you get (but you never know) takes a lont time to charge so I'd imagine it's more like 5mA? Not sure if it's regulated or tapers, just that it took a couple days on my test batt, which I think was <2.8V, from a keychain LED light.

The cheap charger is awesome, much better than mine. Mine was just a redneck experiment to bump voltage thanks to the alert time. I rarely needed it so I wasn't motivated to spend time making it nice and easier to use. I did find a different charger online, maybe a couple years ago, but I did't like it and tossed it. Then I got this new one, which is perfect, so I tossed my redneck version.

I bought two because I usually do that with chinese electronics, thanks to the very high faiure rate. Plus it's so cheap, why not. Just the USB-C cable that comes with it is worth the price.


If you're into stuff like this, which it seems you are, I have a 2032 related story you might like: I love the little LED keychain lights, which I use daily. I don't do keychains, but I have one in my pocket at all times, at least one in any jacket I have, a few in the car etc. This looks like the ones I use: https://aliexpress.us/item/3256806169907636.html
I only buy black, unless I put a UV LED init, then I use purple.
They some with two 2016 batts, which makes them very bright and is also over driving the LED and sucking the much smaller batts down pretty fast. You may know the 2032 means 20mm x 3.2mm, which is the same size as two 2016's. One 2032 is a great voltage match for the LED to last, power drain drops drastically, plus you have >2x the ampacity. Brightness is less of course, but I think it's just fine, better actually. If I need bright I have real flashlights.
The batt life is so long that I usually lose or break the light before I need to recharge it. So I end up charging the batt and putting it in the next light. As a bonus I have two 2016 batts left over for each I do.

When I went for my airbag recall they "offered" to replace the batt for a mere $32.46. That was four years ago this month, so I'd imagine $40+ now? I saved the quote because I couldn't believe the prices, which included two tires for $892.80 and motor mounts for $1773.30. Hard pass, thanks, I'll never return. No wonder they offer loans for the service dept.

If you charge the 2025 I guess you don't need to do the mod, but I like modding things. I also modded the key buttons to be harder to actuate, because they'd often get pushed in my pocket. One morning I came out and my trunk was open, so it was like that all night, which was the last straw. I also disabled the stupid Panic button altogether. Those mods are easy, but getting the key apart to do them is not so easy. Well, not easy if you want the key look nice when you're done. If you/anyone want that info I did save pix and notes. Lotta pix so I don't think I should post it here, but I can upload it somewhere and give you a download link. Or maybe I could post it here zipped?

The pix below shows the mod to accept the 2032. Note the little yellow lines noting the plastic I removed.
There is no rubber seal, it's more of a cushion hold the batt in place. The cover will bulge a bit, which I found annoying, so I used a Dremel and a sanding disc to thin the rubber cushion that presses on the batt and problem solved. I can take a pix if you/anyone want to see mine.

 

Well, maybe not. Sometimes it won't let me post pix and I've yet to figure out why. Guess I'll try again tomorrow?

Also, if I try dragging the pix to the post it'll say: "Trying to add an image? Please use our image upload option in the toolbar above."
Yet there is no such option on my toolbar

 

I guess it did take. Stupid computers.

 

Damn. You went long-form. And with practical solutions too, outside the official channels. Better be prepared for that forum sponsorship "proposal"!

I love your ingenuity, it's almost a lost art nowadays. Ordered a bunch of those flashlights as well. Why not, before The Ursula starts charging me for my packets.

As for the charger, I was thinking of something way more complicated, with constant voltage / current and all that crap. In fact, I highly doubt the cheap charger is anything more than your setup, or probably a voltage divider of some sort. The chinese make some fantastic stuff, but I'm actually more interested in such dirt cheap gadgets that help me just... tinker.

Will do the key mod as well, combined with the charger to bump the battery, it should help me get enough life for my key, until I manage to get the german nanny coded out, or until I finally get my own Star (it's always falling behind in my overpopulated task queue).

Out of curiousity, what is your trade, if that's what isnpired you to do stuff like this? Or are you just a tinkerer by nature?

 

I'd imagine the chinese charger has a voltage divider, but just a guess because that would be the simplest and cheapest way. Anything more complicated would not do a better job, but if it did use a divider then it just might last forever and they can't have that. I suppose I could crack it open, but I just don't care.

I was born this way. Been tinkering as soon as I could operate a screwdriver. 5yrs old, maybe earlier. One of those people who takes things apart to see how they tick and modify just about everything, just because.

I tinker with the Benz too, but it's just not the same as old school hot rodding. Fyi I used to have a '99 CLK 320 Coupe. It was the metallic maroon color. Looked sweet. Not much I could do to make power so I put N2O on it. I think was about a 150 shot? Years later I gave code P0400, EGR fail, but the EGR worked fine. Can't fix what ain't broke, and can't smog it with that code, so the car was done and I sold it as a parts car.
What year is yours? Do you mess with it at all, or bone stock?

I don't think anyone would sponsor me for anything, I'm not PC. Plus, some things I mod upset people, sometimes really upset them. I've even been kicked off a couple forums and forum Moderators that disagree with me have edited my posts to delete what they disagree with, or edit to make my argument look weak or dumb. Nothing like being censored by a small person with too much power.

You mentioned "almost a lost art", which makes me think of this South Park episode: So I might be in high demand one day, like that old handyman. As time goes by I do notice that fewer people know how to fix, maintain, or operate things I assume everyone should know. Like those car mech vids where a customer shows up because a 3 yr old car won't run, then the mech finds out the oil was never changed.

 

I know what you mean, I was like that too. Took years of my parents saying that "whatever I touch does not see the light of day again" to become the go-to for ressurecting crap.

The clk is my first car, love it to death and will never sell it. After undoing the pointless MB excersise of trying to make it ride sporty, while making it ride crashy... By fitting complete C-class comfort suspension and oversized 16-inch tires, it rides like a dream. It doesn't have the floatiness of the 221 over larger undulations, but it irons out the annoying imperfections like bridge joints, road cracks, and belgian pavement just as well, if not better. It helps that I did multiple interior teardowns in search of squeaks and creaks.

When I did that, as I was redying the now purplish rear shelf, I was very disappointed of the way it mounts with rattle-enhancing clips. So I drilled the mounting points out, added threaded nut rivets, screwed down the whole shelf tight, and finished with decorative bolt caps. A little model of the car is mounted on top of the emergency kit, for the delight of gas pump attendance. To finish the headliner, which also had to have the factory-installed rattle generator removed, I added neodymium magnets to the front of the sunroof shade, to stop it from opening on hard acceleration (read - all the time).

At the same time I installed a reference level sound system (Brax speakers and 8-channel DSP) with A-pillar mounted mids+tweets, and did a complete sound insulation with 2mm virgin butyl, not the crap car audio stores sell. It sounds as if the band is live in front of me, and the midbass gives me foot massage...... To put it this way, I always take the longer road, whenever I'm going. For convinience, I wired an apt-x bluetooth receiver to the factory radio, and installed a wireless phone charger in the small compartment below.

There's a ton of lighting mods I did as well. 211-style HID bi-xenon projectors; high power LED brake lights, turn signals and high beams; modified OEM fog lights for 180 degree light, brilliant for tight, dark streets. Then, just for fun, I added dim amber leds to the interior door handles, and ran wires from the overhead light to the exterior handles, so they light up when the car is unlocked, like on newer benzes. To finish it off I programmed and wired a small arduino to the turn signal circuit, which gives me one-touch-for-four-blinks feature, brilliant.

Another time I reverse-engineered the geometry of the boot-opening springs on the 211, and machined new brackets to make the boot lid swoosh open more smoothly. Great days! The latest mod is from a few months ago, when I mounted metal brackets under the seat mount, extending over the floor mats, to prevent the seat rail from scrunching the mats when pushed forward.

Man, I've done a lot now that I think of it. I should post some pics in the CLK forum with these mods.

 

I usually wasn't worried about whatever working again, the goal was to find out how it worked. Unless my goal was to repair it, or modify it, which is the most common thing I do these days.

Hopefully you won't get a CEL that won't go away, because I wanted to keep my CLK too. Most all cars I've owned had this issue and, the car is done. So I sold the CLK for like $2500. My current car has the same basic issue, but luckily I have a work around to get it to pass smog.
Mine CLK rode way too soft so I put Bilsteins all around. I think the oem are Bilstein, but completely unsat. So I bought fatter and stiffer Bilstens and it was perfect. I treat vehicles like a toy that happens to double as transpo, so performance comes first.
My headliner did start to drop in a couple places, but I simply used little pins with a corkscrew shape to screw it back up. The sunroof shade never moved, but like my current car, I never open it so that probably extends its life? I also rarely listen to the stereo so oem was fine for me. I like a nice stereo, just not enough to install one.

I'm also the opposite when it comes to lights. I prefer dimmer lights or none at all. Bright brake lights and signals are light pollution imo, they hurt my eyes and especially my night vision. Some people install even brighter than modern oem levels and I don't know why. I know people think it'll help with their own personal safety, but at the expense and annoyance of everyone else. E.g. a couple months ago I was behind a truck with nuclear brake lights. He put red light bar across the back. Picture an off road light bar, but red. Think that's bad? It was also strobe. Grade A Ahole. When I first saw it, which was in the early AM and completely dark out, I was in partial panic mode because clearly a UFO just landed. It was literally blinding and so incredibly annoying that I fantasized about how I could F this guy up and not get caught.

The lights on my CLK were awesome. Bright enough that anyone can clearly see them, but not pointlessly bright like all modern cars. Dimming my light is on my list of things to do, but it's way down on the list.
Another thing, at least for me, is I do not want lights that stick out. Not too bright, not too dim, certainly no extra lights. Like my lic plate lights are very very dim, but that's for my safety. If they're off I may get pulled over, but just enough you can see they exist is good. Generally anything that doesn't look oem increases your odds of getting pulled over, and a ticket, including things like A pillar speakers. Police here profile, so anything, even how dirty your car is or how long your hair is, can make the difference between them driving by and a very unpleasant experience. Even females have problems driving a truck because the cop assumes it's a guy with long hair. It took a few years for me to figure this out, then I went from being pulled over weekly, and usually getting a ticket, to years between pullovers and rarely a ticket. So you need to be lean cut, clean and newish car, and looks bone stock. I also learned a Benz is an extra layer of protection and I call it my "get out of jail free car". It's like I'm invisible to cops. No joke. Come to think about it, I've never had a ticket in a Benz, and I've broken some serious laws, but nothing... If I had some pos I would've lost my lic, which is exactly what happened when I was 17.

My current interior lights light up when unlocked or you open the door, so I removed all the bulbs. Plus the door markers, glovebox and trunk lights all removed. I only wish there was also zero light flashes when it locks/unlocks, which is doable, but not easy.
The dash lights are way too bright imo. The lowest setting is what I think should be the highest, and it should go all the way to off. Older cars do that, and I could easily adjust those that do not. This car I could but getting the dash out is nothing like any other car I've had. The CLK was the easiest. I could pull it out in about 5 seconds, as I imagine you know, then disconnecting the wires took maybe a minute?
The Command center for the radio etc, also waaaay to bright, so at night I try not to do anything to trigger it.
I don't have fog lights on my current car, but have had them on a few cars. I just didn't understand why they exist. When I turn them on I just see more fog and less road. At best, if the fog is right, I see more fog but the same amount of road. So there was no bennie and I always wondered why they exist. Do they do anything for you, or just for show?

Another gripe is modern cars often have low beams that are blinding to oncoming traffic. I often have to hold my hand up to cover their lights so I can see the frikkin road. How is that legal? I often wear sunglasses at night because of this. Then to add to it, a ton of people have full size trucks and SUV's so with these F'ers behind you at a light your car is lit like the sun. Do you guys have to deal with that crap?

The hood spring thing sounds cool. I'm used to old hoods that you manually lift and insert a rod to hold it, so modern hoods are already a huge step up for me.
My car scrunches the mats too, but only because I have those mats that cover all the visible carpet everywhere front and back. I just let it scrunch, but I rarely need to so no biggie.

You might like my "Chevota" truck (Toyota mini-truck, I will never own a full size truck or SUV). I completely disassembled it, and by completely I mean every single bolt and fastener everywhere. I cut the frame up and stuff it in the trash, along with a lot of sheet metal and other parts. Then made an entire new frame, plus a 14-point roll cage, from scratch. Put manual brakes on it because power brakes are a problem off road. The engine and tranz are Chevy. Rear axle is a Ford 9", but with the Toyota axles and brakes. Of course Bilstein shocks, but I modded all of them, and two I made into pneumatic springs that were adjustable in both force and rate. Radiator was under the bed. I replaced a lot of the oem sheet metal with Alum. 24gal gas tank/fuel cell. Roll cage was tucked in so well that most people, sitting inside it, didn't know it as there. The only thing I didn't do myself is bore and deck the block, turn and balance the crank, and change the driveshaft lengths. I also had the cam cut, but it was cut to my unique specs. I also use a hydraulic flat tappet cam and lifters, but with lash, which I mention because it works awesome but nobody does it.
The distributor is the old points style that I heavily modded, so no points and very different mechanical and vacuum advance to give a drastically different spark curve. Pretty much everything in the truck was either made from scratch, or was one of several brands of oem parts that I modified, or aftermarket parts that I modified. Not sure there was anything I didn't modify, excluding bolts. It has 33" tires yet still sits stock height and the whole truck weighs less than stock. Oh, and I added air conditioning, which it never had
Remember I said I usually sell cars a "parts car" because they won't pass smog? That's how I got this truck, for $800, because the poor guy couldn't pass smog. So if you're into fixing cars there's an endless supply of them here that won't pass smog, for cheap.
One bennie of making a frame is a loophole to bypass the smog laws. Like a gun, the frame is the car. So make your own frame and it's no longer whatever it was, it's now your own custom made car, no make or model. Here's the beautiful part; you can put any engine you want in it, but you have to comply with emissions for that engine. So you get one old enough that has little or no smog bs. Ironically, installing a substantially cleaner newr engine is just about impossible because you'll never get it to pass smog. A friend went this route, which cost many thousands extra, and failed. Go with an old gross polluter and you're good to go. So smog was part of why I did it. The other part was I saw two guys in the same model truck I had, roll it. Picture the cab crushed down to be level with the hood and bed, with two grown men trapped inside. They were stuck there until the Jaws of Life arrived which took about two hours. It had to be extremely uncomfortable, and no doubt in constant fear that it'll catch fire. Uggg, hard pass for me. Oh, and my first trip out to the desert after I put the cage in, I rolled it :o The cage held it tight and I drove it away. A new hood, door, grill and windshield, est $300 total, including paint, and it was good as new, more or less. If no cage it would've been destroyed.