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Post by werdna on Sept 26, 2023 9:15:12 GMT
Had a tiny (and I do mean TINY) impact on the RNS corner of my 2018 Hybrid Rev. Thought nothing of it until 10 days later when the 'Blind Spot Monitoring System failure" appeared on the dash. Fault code reader indicated the RNS unit had failed (don't see how - it wasn't touched at all in the impact?!). Sourced another unit from Bay and fitted it - all was fine ............until a week later when the fault warning on the dash appeared again. Does anyone know why the fault doesn't show up for a period after any impact and how to rectify the problem - I think I'm looking at a new unit from the main dealer - please tell me I'm wrong!!
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Post by charliefarlie on Sept 27, 2023 12:09:38 GMT
Had a tiny (and I do mean TINY) impact on the RNS corner of my 2018 Hybrid Rev. Thought nothing of it until 10 days later when the 'Blind Spot Monitoring System failure" appeared on the dash. Fault code reader indicated the RNS unit had failed (don't see how - it wasn't touched at all in the impact?!). Sourced another unit from Bay and fitted it - all was fine ............until a week later when the fault warning on the dash appeared again. Does anyone know why the fault doesn't show up for a period after any impact and how to rectify the problem - I think I'm looking at a new unit from the main dealer - please tell me I'm wrong!! It’s considered both friendly and good mannered to introduce yourself and say hi when joining the forum. You will get the best incredibly detailed advice from the very knowledgeable members here and that’s on anything you night like to ask questions on. Just a wee heads up to how it works here. And welcome to the forum 👍👍 |
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Post by shcm on Sept 27, 2023 18:50:10 GMT
My advice would be to get the stored fault codes relating to BSM read and don't just assume the unit is "bust".
The thing may appear to present a nice simple operation but there's a very long list of engineering challenges that have been addressed with these systems that most people, to be frank, wouldn't even begin to occur to them. I could write you a book on it which would double up as a very effective insomnia cure.
e.g.
1. while the units can tolerate some misalignment and compensate for it, very often some form of initial alignment is needed. It was certainly the case in the past, but misalignment algorithms have improved. A small "bump" has the potential to misalign it. Often they need some for of initial calibration too. So just swapping the unit may not be the best of ideas (new unit internal calibration may be wrong)
2. At the frequency the things usually operate at (77GHz) the bodywork shape that the radar is "looking through" and types of material used in the bodywork can significantly affect how the radar "sees". It may look simple enough, but believe me, there's an whole heap of work done to get it right. Certainly this is the case for the forward looking ACC/AEB radar and I know in the past there was great concern about how rear bumper material/shape/repair would affect blind spot detection systems. If you compare the radar with light, you can kind of think of the bumper as a piece of curved glass at the radar frequencies. i.e. a bit like a lens the radar is looking through. So a slightly deformed rear bumper (like from a knock) has the potential to cause problems.
If the radar is communicating with the rest of the vehicle but not seeing anything or is misaligned to the point where it needs "human assistance" to put it right, well, put simply, it very often needs a bit of time to work that out. e.g. if it's not seen any other vehicles, is it blind or just driving on exceedingly quiet roads?
So, the fault codes, that hopefully are stored in the unit, are there to help!
Hint: I've 20+ years experience of automotive radar hardware PCB design/development so I don't have a clue what I'm talking about.
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