Hi. Sorry for the long post, but I have a problem that has literally resulted in 3 weeks worth of shop time over 3 months without resolution. So here's the long version.


I have a 2005 W211 E500. Have had a steady SRS warning since late February. In early March, I took it in for service to a local mechanic I trust. He said the SRS error code was related to the weight sensor in the passenger seat. He checked, and the weight sensor module showed a fault in the left front sensor. He replaced all four sensors and it still showed the same thing. So he replaced the module. He only charged me for the module.

But the new module will not "calibrate." According to the mechanic, the program will go halfway and stop. It will give an error that apparently indicates the seat frame is bent. The seat works fine - rises, moves forward and back, etc. without issue. So he took the seat frame out and there is nothing he can find wrong with it.

We took the car to another mechanic - same diagnosis. But when he was told the older module showed a different issue, he said the likely problem was both modules were bad. He suggested we take it to Park Place, my local dealer, and have them try a third module.

Park Place says my seat frame must be bent because the code says so, and there's nothing else to look at. They refuse to try a third module as they say the issue is clear. Yet they refused to show my mechanic where the frame was bent or explain why the seat still works. They want $1400 plus labor to fix the seat frame, but would not guarantee that the repair would actually correct the SRS error or even that the weight sensor would work correctly thereafter.

They called about an hour ago and claim the left side has "lost electricity" and they want another $99 to "diagnose" that problem, which they admit happened in their shop. I told them I wanted to just come pick it up.

Aside from what seems like pure crookedness from Park Place, anyone have any idea what the issue with the weight sensor could be?

Thanks for the read!

 

When calibrating the weight sensor with STAR, do not move the seat until it stops as directed by the instructions, instead move it just a few seconds in each direction until it is ready to calibrate. This is a software bug in STAR I think, or just something else from MB that doesn't work s it's supposed too. I'm not sure how your indy is calibrating it since it requires an expensive set of butt-shaped weights made by MB as a special tool.

 

Thanks for the reply. My mechanic, the second guy and the dealer all get the same thing when they try to calibrate- it goes halfway and stops. I'll let them know, but my hope is that at least one of them did it right.

 

As I understand it, the weight control module will not "zero out" (calibrate) the passenger seat as it reads the weight sensors as not being properly aligned/balanced/something. This means, to the several mechanics, that the seat frame is bent. But the second guy said it has to be noticeably and unworkable bent to make a difference. Which it is not.