Re-Calibrating Weight Sensing System (WSS)
 

Hi, anyone had success re-calibrating the WSS? I just got my Autel MaxiSys Mini scanner and tinker with the WSS due to seat belt alarm pinging me on an empty front passenger seat. Well I fixed the seat belt warning but couldn’t finish or pass the last stage of adding on 37.5 lb. Now the test isn’t complete and showing SRS light.

I've never heard of anyone needing to, they just replace the sensor when it goes bad. I don't know much about though.

I didn't know that the sensor could be re-calibrated.

You definitely able to with SDS or my Autel MaxiSys Mini that I just bought from friend on this forum.
https://cimg9.ibsrv.net/gimg/www.mbw...6cdef9074.jpeg

never done it without the special weight tool but I've heard of people stacking weights on the seat to the approximate weight

thanks, maybe that’s my problem, NO special weight tool. I stacked 70lb dumbbell (that’s what I curl with, lol) and still was under 35.5lb needed for process. I’ll try 35-45 plates next over a booster seat.

The distribution of the weight is important as well, take a look at the shape of the tool.

45lbs & 35lbs plates didn't work, really scratching my head but gonna keep trying. Thanks!

Shop shouldn't charge much to recalibrate the system if you tired of messing with it. Just ask if they have the tool

Thanks knowbenz, appreciate your inputs. My last resort would be so. Thinking of putting my 40lb kid on seat to see if that work. 😂 Will update.

The dealership has a special, and heavy, butt-and-legs shaped weight that is used to calibrate it..in stages. Also make sure your seat is not all the way back or all the way forward. Somewhere just forward of the rear stops and level seems to work good. A dealership shouldn't charge more than $200 to calibrate it for you.

I had to take out the P side seat (I ruined the perfect leather seat bottom on my 09 E63) and swapped in a very nice seat from a wrecked 09 CLS63. My indie did not have the WSS heavy tool to do the proper calibration, so I took it to the dealer and they calibrated the seat for $175 (1 hour) to clear the SRS warning light. No issues.

MSG_55G, is this now working? If not, did you perform the zero point setting of the seat prior to adding the weight to the seat?

Not fix yet. I stopped messing with it for now. I did perform zero settings procedure first but failed weight steps all the time due to lack of weight tool

have to fix red battery light.

Front/bottom, front/top, rear/top, rear/bottom, correct? With head rest lowered. I can post photos of the procedure if it would assist. Let me know.

Let us know about the solution to your battery light.

Thanks Barry, please post photos of seat positions procedures. That’s one confusing step to follow. I will certainly post read battery light solution once I narrowed it down.

He's talking about not having the correct set of weights used to calibrate the system

I have successfully performed calibration of the WSS using rotors and small items to complete the weight. But I have always used DAS. It's tricky but can be done. and yes, weight distribution is a key. The WSS has 4 different sensors on each corner of the seat.

Try these steps. This is from the simulation so it deliberately added a fault at the end. Excuse the crappy photos as the computer uses Windows XP and remains standalone.

https://cimg7.ibsrv.net/gimg/www.mbw...ebc6c8958d.jpg
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https://cimg3.ibsrv.net/gimg/www.mbw...a237fdcf13.jpg
https://cimg4.ibsrv.net/gimg/www.mbw...cefd7f05af.jpg
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https://cimg9.ibsrv.net/gimg/www.mbw...9b40b45c99.jpg

Thanks so much for info, gonna jump back in this project now that I fixed the red battery light problem. Gonna start a thread to share my journey on the diagnosis and final resolution.

I asked MB last year to calibrate the seat while it was there for some recall work. Of course the technician couldn't do it. Told me the Airbag and WSS control module must be defective and needed to be replaced for over $1500. NO THANK YOU!!!!

I calibrated my seat today with a towel to protect the leather, a wooden board to distribute the weight evenly, dumb bells and water bottles. That way I was able to precisely put 17 and 45 kg on the seat. Problem fixed. Cost? $0!!!

Success! Awesome! Thanks, Mack!

awesome! Was thinking on doing the same thing using my Brittanica encyclopedia book. Figured dealer would want to replace whole module instead of just calibrate WSS for $185

Even if they would replace it, it has to to be calibrated. Every time something is being worked on the seat it needs to be done or the SRS light will be on.

Most customers have no clue and just say yes to everything they are been told by their SA. It’s good for business. It’s bad for the customer and their check book.

Most if not all mechanics at these dealerships make money only if they “find” and repair stuff. Regular stuff done on the car and they don’t make anything. It’s pathetic their system. Knowing this I bet they never even started the process. They simply seemed it bad control modules and hoped the customer will agree.

To be fair, some of the older cars with wear on the bushings can be stubborn. I'd be willing to bet he made a couple attempts and kept getting errors then quickly threw in the towel. I've had a number of them take multiple attempts and shaking the seat around to set, even with bad bushings. Still, condemning all related parts is a terrible idea, we live in a time that so much information is available to us. Making one bad call that can be proven wrong can be the end of the customer. Loosing one customer may be acceptable to some but then it becomes one more, one more, one more, and people bash you online leaving you with little business.