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Post by 710motorsports on Dec 1, 2017 23:20:22 GMT
Does OBDEleven allow optical bus diagnostics? I haven't found it anywhere and we seem to do a lot of audio and gateway issues, so this would be helpful.
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Post by cradv22 on Apr 6, 2021 19:54:37 GMT
Hello everyone,
Anyone have any luck or can suggest how we can run an optical bus diagnostic on OBDEleven? Need to run down a faulty component of the system preventing the MMI from operating on 2011 Audi A8 D4.
Any help or suggestions would be greatly appreciated.
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Post by dv52 (Australia) on Apr 7, 2021 1:23:24 GMT
hmm........ I don't believe that OBD11 has a facility for the type of optical diagnostics that is possible on another well known device - a situation that should be rectified IMO. however, it may be possible to manually diagnose the problem (without OBD11) using Audi's optic fiber by-pass loop (part number 4E0 973 802) - see picture below (you can get alternative versions on eBay): I'm not sure if you are aware, but the MOST bus has a ring topology like this: So, the ring topology means that for successful communications, each module must receive data from one side of the MOST bus and pass the same data to its neighbor on the other side of the MOST bus until the message is received again by the module that initiated the communication
Of course anything is possible - but if the vehicle has not been in an accident, or if the fiber cables have not been broken by rough treatment, it's unusual for the Optical cables, themselves to be the cause of the fault. More likely, the problem will be in one (or more) of the modules - which results in the inability of the module(s) to pass-through the MOST data to its neighbor (thereby optically breaking the ring architecture) The loop device above works by by-passing the module entirely to reestablish communications on the ring. To use the loop, unplug the MOST connectors from a module and plug the loop in place of the module. If the module is faulty, the other modules will start communicating again. If the fault persists, re-connect the module and try the same procedure on the next module.
The other possibility is that the MOST fault could be electrical, rather than optical. By this I mean that the fault could be in the ring-break-diagnostic wires that form the hub-and-spoke topology in the diagram above. To test this, go to Start ring break diagnostics in the module Live Data function and initiate the procedure. I've not used this procedure personally, but it should be operational in OBD11 because the module itself performs the test - so it should be the same as every other procedure in the module Live Data function.
Don
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Post by cradv22 on Apr 10, 2021 22:22:21 GMT
Really appreciate the breakdown of the system. I’m trying to isolate the modules which are causing the system to fail the start up check of the ring. My MMO system starts and shuts down. I’ve tried running the ring test but can’t figure out how to get the output results to see where the check fails. I’ve purchased a couple of loops so I can isolate the modules. Other than the Bluetooth and Amp not sure where they are in my car. (2011 Audi A8 D4). Would you happen to know how I can see the results of the ring test in the OBD11 app. I use the iOS version. Again really appreciate the help and advice. This is why forums are always my go to for info.
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Post by dv52 (Australia) on Apr 11, 2021 0:41:31 GMT
cradv22 : hmmm........ as I said, I've not personally run the ring-break procedure, but when the dealer tool is used (ODIS), an additional "optical substitute control unit" VAS 6778 is also used Here is the screen shot from OBD11 using iOS (select Live Data from the hex5F module main screen and enter "Ring" into the search box - as shown in the picture):
My apology - I referred to "Output" in my first response, it should have been "Live data".
As for your connector identification issue, here is a view of the rear of the MMI showing the MOST socket Notice how the MOST bus has 2 x optical fiber ports - for the 2 x sides of the "Ring" topology. The picture is from a high-end MMI - but some of the lower spec MMI's have the MOST socket on the LHS of the large Quad-connector.
The MOST 150 optical bus consists of the following modules: the MMI module (above)
the Dashboard module if your car has AID
the Digital Sound System (i.e. the external amplifier - j525) if fitted.
I assume that your car doesn't have a TV - if it does, there will be another MOST socket on the rear of that module
Don
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Post by cradv22 on Apr 14, 2021 0:52:36 GMT
Thank you for the information. I ran the live data option and just received a very long string of numbers as a result. Any idea what this means or how I can decode the result? I know from my general code scan that the radio module and multimedia module are not responding to scan.
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Post by dv52 (Australia) on Apr 14, 2021 7:40:16 GMT
cradv22 : not sure , can you post-up a screenshot? what happened when you used the loop?
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