From the manual: Desiccant cartridge replacement

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hallcp

Well-known member
Joined
Jan 7, 2019
Messages
127
Now that I have an electronic copy of the Mercedes manual, I am able to find some things I was curious about. At the top of my list was the mysterious "desiccant cartridge" which must be replaced every 10,000 miles or annually according to the manual. What is this thing? No other EV I know of needs such a thing. The only desiccant cartridge I know of is in the air conditioning system, and you only replace that rarely.

Well now I can tell you that this is a real thing. The high-voltage battery does have it's own desiccant cartridge (still don't know why). The next question is whats involved in replacing it? Here are the steps from the manual...
  • Raise vehicle with lift
    Remove side underfloor paneling
    Remove screw plug (1)
    Replace desiccant cartridges (2)
    Screw in plug
    Install underfloor paneling
    Lower vehicle

and here's the accompanying photo:

dessicant-photo.jpg


I haven't found the part number for the cartridge yet, their parts catalog is as complex as their workshop manual. But since the whole point of replacing this cartridge (in my opinion) is to maintain the battery warranty, doing it yourself might not count. Plus do you really have to drop the whole floor pan??
 
idk how well you trust partsgeek fitment notes...

https://www.partsgeek.com/ss/?i=1&ssq=b250e+Drier+Desiccant+Element&x=0&y=0

according to their site you loose the shipping if it doesn't fit. at home you will be unable to do the part of the service where you test the battery so you might not be complying with the certification. battery service is done under 8 year warranty by the mercedes dealer though for free. after 8 years i imagine you would resort to these products and biannual computer testing if ever. here's the maintenance schedule.

http://assets.mbusa.com/vcm/CAC_RAPMD/14Belectricmaintenancebook.pdf
 
I had this done last year by MB of Buckhead, Atlanta. Of course, they will try to sell you some other service like change the break fluid ($150+), wiper blades($90), etc. It’s up to you if you want this extra service. However, in my case they found that my 12V was on its last leg. They replaced it under warranty and also the desiccant cartridge plus main battery inspection. All done within 1.5 hrs.

My $.02,
C
 
ust curious which is more important the annual replacemnet, or the 10,000 miles?

I just purchased a moderately used 2016 and it had the first set of both A service and B service with the later completed at about 17,500. in May of 2018

Car has only been driven about 5,000 in the next year prior to being returned at the end of the lease , but the display say another B service was needed about 1500 miles ago.

Car was not sold as a CPO, but instead auctioned. I purchased it from the used cars who seemed to think that all required manitance had been preformed.

Local Dealership ( not involved in the lease) is recommending an A service which seems to be mostly related to the Desiccant.

There was discussion if this was a warranty service, but they do not believe so and want to charge a little over $in the low $200 for the A

DOes this sound reasonable?
 
Check the warranty manual, I believe it states that the desiccant replacement is entirely free of charge. But it is time dependent. That the replacement must be within 1 month of the previous year's replacement. So, replaced May 2018, replace April, May, or June of 2019.

And you are damn right this is a nuisance service. Only MB uses the desiccant in the battery (Smart ED as well), and it is to guarantee that you bring the car to the dealership, so that they can up-sell you other services, and conveniently deny you battery warranty service should you fail to have the desiccant changed.

Tesla made the battery packs for the B250e and Smart ED, yet no Tesla vehicles have battery desiccant bags. Why is that? Because it is not needed.
 
Genuine Mercedes-Benz Air Drier 789-340-33-00

So if your looking for this stupid desicant cartridge thing. You take off the drivers side paneling under the car, just enough to drop part of it. Think 10 nuts sized 8mm and 10mm. I think the entire pan has like 40 nuts.

Look for the high voltage circle and a badge that has a Tesla 877 number. You see a pic of it on the pdf on a prior post above. It sits behind the drivers side impact battery protection bar. Literally look at the battery itself and be in the drivers front corner of the pack.

It takes a T90 torx to remove it, that fits a half inch ratchet/spammer. They cost $20 on Amazon.

Hope that helps.

Also you need to check you passenger front wheel speed sensor. It goes in your electric motor. That sweats and it will literally brick your motor. If it does brick it, it cost 6k to pull and freight to Southern California to rebuild. Mercedes and Tesla will not support buying a new motor.

https://youtu.be/txD7u2DKanE
 
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