huntec Posted January 20, 2017 Report Share Posted January 20, 2017 Greetings! looking for ideas in diagnosing my 2010 V50 (Rdesign AWD M66 trans) I've reached a bit of a dead end, I'm scouring the forums for additional info but wanted to also put out a request in case there was new or additional knowledge. Anti-Skid service required on accompanied by BLIS service required (odd, eh?) Vida codes for communication drop out Changed- Fluid(looked clear), Pump (was still functioning), Filter (not too clogged), had shop remove and send DEM out for rebuild, even with all this still the exact code. Monitored live data feed on VIDA: Pump current is around 1A, never exceeding 1.5ish on load dropping down off load, pressure varies normally but no comparison data to ID, idle pressure and off pressure spot on, Temp sensor reported a believable number but did not confirm. Monitored Steering angle and all believable values, monitored yaw and accel, all believable (not sure what tolerance is but I would assume that these would throw their own codes.), only other codes are an occasional wiper sensor code, BLIS sometimes says service required but it's infrequent and nothing logged in vida, and had one clutch sensor code from a few drive cycles ago, nothing concrete or related to the main AWD codes. Here's where it gets tricky, the reported velocity for the DEM is garbage compared to indicated velocity AND BCM reported velocity, when going 40KM/H, the BCM reports 40KM/H and the DEM reports 70KM/H, and this discrepancy exists across the range. Not sure where it gets this info, how it's parced or anything of that sort to compare against, hoping someone had some data on this correlation. Furthermore, even after it throws the communication code there's no interruption in data received by VIDA, it never actually disconnects. It just throws the code and continues to transmit but I loose AWD. Assuming the DEM velocity discrepancy isn't a set workaround or within tolerance, my running hypothesis is that the DEM velocity read out is garbage and during sometime in the drive cycle (maybe load dependent or something) it compares these values between the BCM and the DEM and when it determines the DEM values to be garbage, it considers the DEM to be damaged and junks it throwing the light and code. With no hard details, however it's almost impossible to confirm or deny (this was passed on to the shop it's at, however, and they're going to see if they can find out something about it). Beyond this, I'm at a loss. Shop is looking at it again since they recommended DEM rebuild and it wasn't the problem, but probing for some info on my own to aid in the process. Thanks y'all! Link to comment Share on other sites More sharing options...
hootie6828 Posted January 20, 2017 Report Share Posted January 20, 2017 Anti skid service or awd service? What are the actual codes you are getting? Communication codes usually indicate a can issue, not an actual fault in the component. Link to comment Share on other sites More sharing options...
huntec Posted January 21, 2017 Author Report Share Posted January 21, 2017 Word for word anti skid service required Code BCM-0095 Diagnosed as bad dem. Can issue has not been explored... Interesting. Link to comment Share on other sites More sharing options...
hootie6828 Posted January 21, 2017 Report Share Posted January 21, 2017 Do you always get the anti skid and blis warnings together? Link to comment Share on other sites More sharing options...
huntec Posted January 21, 2017 Author Report Share Posted January 21, 2017 Yes, anti skid service required never comes on without blis functionality reduced. That said blis continues to function after that warning is thrown. Link to comment Share on other sites More sharing options...
hootie6828 Posted January 21, 2017 Report Share Posted January 21, 2017 So the only modules that share the communication wires on that leg of the network are the DEM and the SWM, which would explain your anti skid message and the lack of awd. I think that something is taking the network down momentarily, possibly quick enough that you can't pick it up on vida. I think you are chasing your tail on the speed reference values. I would test the communication wires first, check resistance in the wires. If you know the DEM is good, could be a fault in the SWM as well, I have seen bad these cause some really goofy intermittent issues. I need to do a little more research on the Blis issue, because I didn't see any obvious connections, but that may be the key to narrowing it down. Link to comment Share on other sites More sharing options...
huntec Posted January 21, 2017 Author Report Share Posted January 21, 2017 Interesting, would a bad SWM cause any other symptoms I can look for? I literally just got the thing so I haven't observed any of its quirks yet. As a note, there was an old VIDA code that triggered once or twice (according to drive cycle count) since the trip from florida for "auto windshield wiper button on too long" (Code not available as it was cleared at the shop... wish I had it), Which is strange because I don't have auto windshield wipers as an option on the car. As far as I can tell the car never had them, no stalk no sensor cluster. I thought it was just an unrelated quirk, Is that handled by that module? If so, it maybe time to hone in on it. As an aside, on the drive up from Florida (Yep, bought the car in Florida and drove it home, AWD service didn't come on until I got to the hilly areas of NY) I did get the "Blis service required" (Note, different from the Blis reduced functionality), but it was pouring rain and didn't come one twice in a row, a restart fixed it. As for Blis and it's connection, apparently it has some communication with the DEM according to the shop who had to call Volvo for answers, they believed the DEM was taking out the BLIS, but beyond that I don't have any further information yet. Those were the only "what I thought were unrelated" quirks that I found. If I can find the code for the wiper button on too long I'll post it up. The shop has it now since their DEM recommendation didn't go so well but it's been a two way conversation which is nice, I intend to share what I learn here. I might go over with my multi-meter and ask if I can start probing, we'll see what they say because checking the can wiring sounds like the next step for sure. I look forward to what you find about the blis connection though, they did not elaborate on the level of communication between the modules and I must say being in the dark is not terribly pleasant lol. Thanks for your help! Link to comment Share on other sites More sharing options...
hootie6828 Posted January 21, 2017 Report Share Posted January 21, 2017 I am pretty sure that the blis does not get any info from the DEM, although it is activated over certain speeds, which it would pick up from the bcm. The message may be coming on simply because there is a fault code in the bcm. I will try to figure that out for sure, but I am pretty sure your issue is network related. The hard part may be figuring out if it's wiring or a module, but since it seems only be affecting the two modules on that leg, it shouldn't be impossible by any means. Link to comment Share on other sites More sharing options...
huntec Posted January 21, 2017 Author Report Share Posted January 21, 2017 That's extremely encouraging, awesome. I'm going to see what the shop as tried, hopefully we can rule out (or in) wiring since that's easy. I figure even if the bcm needs a rebuild and the swm needs work I'm not flat broke yet... But continuity checks are easy, would you have an easy place to find the wiring diagram? I'm going to check Volvo wiring diagrams website, I know my back Ally VIDA doesn't have the wiring module. Link to comment Share on other sites More sharing options...
hootie6828 Posted January 22, 2017 Report Share Posted January 22, 2017 I have access to a printed diagram, I can get you pin numbers and wire colors if needed. I don't think your bcm is at fault, but any way you look at it, you need to start with wiring. Link to comment Share on other sites More sharing options...
huntec Posted January 22, 2017 Author Report Share Posted January 22, 2017 Absolutely stupendous, I think I found what i need but I'll come up with a test plan and post, at your leisure if it looks along the right track id appreciate the verification. Given its at the shop and they're not open on the weekends it will probably be until Monday. I was more musing regarding the worst case scenario but I certainly hope it's not the bcm. Link to comment Share on other sites More sharing options...
hootie6828 Posted January 27, 2017 Report Share Posted January 27, 2017 Any progress? Link to comment Share on other sites More sharing options...
huntec Posted January 27, 2017 Author Report Share Posted January 27, 2017 You're not going to believe this. I was all set to start checking continuity and really dive in but the shop looked the one place I refused, at their own work. They used the wrong part number pressure switch. The pressure values were totally wrong and it was throwing the whole system through a loop. Got it back yesterday and put it through the ringer, and no more light. Thank goodness they had no ego in the matter because we're it me I wouldn't have looked there. Thanks again for all of your help, if it comes up again at least you've given me sufficient material to create a differential diagnostic plan! Link to comment Share on other sites More sharing options...
hootie6828 Posted January 27, 2017 Report Share Posted January 27, 2017 No problem, glad it's resolved, and that it was easy. Link to comment Share on other sites More sharing options...
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