Seat Belt Retractors Engaging on Altering Road Surfaces?
Thread Starter
Junior Member
Joined: Apr 2013
Posts: 56
Likes: 0
From: Silicon Valley, CA
ML 350 Bluetec
Seat Belt Retractors Engaging on Altering Road Surfaces?
Has any one experienced their seat belt retractors engaging while driving and not stopping?
I've had the things go off (sounds like the squeal from a deap sea fishing reel when a large gamefish strikes and runs) three times over a section of road nearby. In addition to the squealing noise, they retract hard and pull you into the seat.
This has happened three times on a specific stretch of asphalt road where they are doing construction. There is a large steel plate covering the construction area. However, it is almost perfectly flush with the asphalt.
When we drove over it the first time at about 45 mph, we didn't feel any road difference in the car, but the retractors started screaming and really pulled us back in our seats. I tried it again a day later and nothing happened
I took it to the dealer and they didn't see any codes or issues. Passed over the same spot a couple of week later and it did on two consecutive passes.
Tried it again yesterday, albeit a little slower (40mph) because of traffic and it did not re-occur.
Has anyone else ever had anything like this happen?
I've had the things go off (sounds like the squeal from a deap sea fishing reel when a large gamefish strikes and runs) three times over a section of road nearby. In addition to the squealing noise, they retract hard and pull you into the seat.
This has happened three times on a specific stretch of asphalt road where they are doing construction. There is a large steel plate covering the construction area. However, it is almost perfectly flush with the asphalt.
When we drove over it the first time at about 45 mph, we didn't feel any road difference in the car, but the retractors started screaming and really pulled us back in our seats. I tried it again a day later and nothing happened
I took it to the dealer and they didn't see any codes or issues. Passed over the same spot a couple of week later and it did on two consecutive passes.
Tried it again yesterday, albeit a little slower (40mph) because of traffic and it did not re-occur.
Has anyone else ever had anything like this happen?
MBWorld Fanatic!
Joined: Nov 2012
Posts: 6,130
Likes: 1,117
A gaggle of MB's
Sure - it's called "pre-safe" - and the truck is sensing you are hitting that different surface at too high of speed for that surface - it's doing it's job, good news for you... since you were in danger Will Robinson, genuine danger..
Thread Starter
Junior Member
Joined: Apr 2013
Posts: 56
Likes: 0
From: Silicon Valley, CA
ML 350 Bluetec
Thank you for explaining what system is causing this, that explains why its happening and not showing any codes.
I'm surprised that it triggered, given that there was no bump or change in speed/direction. I guess the wheels slightly changed rotational speed when moving from the asphalt to the steel and the sensor picked that up...
I'm surprised that it triggered, given that there was no bump or change in speed/direction. I guess the wheels slightly changed rotational speed when moving from the asphalt to the steel and the sensor picked that up...
MBWorld Fanatic!
Joined: Nov 2012
Posts: 6,130
Likes: 1,117
A gaggle of MB's
The Mercedes system is highly respected in this regard - not trying to bust you out - the system "should" kick in on questionable road/traction/control situations - in this case I would expect it was accelero sensors...
Keep the beat !
Keep the beat !
Junior Member
Joined: Jul 2013
Posts: 17
Likes: 0
ml350
From reading this tread it seems the seatbelt retractor puts instantaneous tension on the seatbelt and then releases it. I was looking for a video on this on youtube and all the one out there use a one time explosion that just pulls it in and then it is spent.
How fast does it retract and then how long until it is released or resets?
Any demo video out there on this type?
Thanks
How fast does it retract and then how long until it is released or resets?
Any demo video out there on this type?
Thanks
MBWorld Fanatic!
Joined: Nov 2012
Posts: 6,130
Likes: 1,117
A gaggle of MB's
What2doo... download and save the pdf Owner's Manual from mbusa.com under the Owner's Support section, then do a key word pdf search for Pre-Safe... Pre-Safe tensioning and Explosive-Tensioning-Device accident system are two very distinctively different systems.. my post was clear, check Pre-Safe, you should be impressed..
