How can I find the meaning + source of this reported Autologic fault?

[Legoman]

Replaced a known dead PDC transducer yesterday from the rear bumper in the hope this would clear a fault from coming up on an Autologic scan. After clearing all the faults and retesting with the new known good transducers installed, the attached error came straight back up again. It's a hard error, meaning it appears instantly again after being cleared. Not an intermittant fault. How can I trace this? There is nothing obvious wrong or not working as you would expect it to in the PDC system.

Link to PDF of Autologic report with error highlighted

[whiskychaser]

Unless there is only one PDC, I am missing something as the link doesn't tell you which one. Are you replacing the sensor with an original part? If not, you may be disappointed. I have about a dozen brand new aftermarket ones (due to a supply error) and none of them work

[Legoman]

Unless there is only one PDC, I am missing something as the link doesn't tell you which one.

That's exactly the thing. I don't understand why there are all zeros in front of the fault listing on the report. Surely there should be some numbers here that represent error codes or otherwise serve to narrow down the source of the fault? Like as you suggested, identifying the exact transducer causing the fault by reference number.

Are you replacing the sensor with an original part? If not, you may be disappointed. I have about a dozen brand new aftermarket ones (due to a supply error) and none of them work

I found the non-functioning transducer by walking around the car waving a piece wood in front of each sensor individually and listening for the beeps inside the car through the open windows. The dead one was the inner left on the rear bumper. I sourced a second hand equivalent from a wreckers, fitted that and repeated the crude testing procedure. All sensors now work exactly as they should. The second hand transducer I bought is healthy. Yet I still have this persistent error code popping up everytime on an ECU faults interrogation and no means of finding out what it means or how to fix it.

[whiskychaser]

Does your car have front sensors too? While you don't get a code, Autologic does say VMR. Not a BMW abbreviation but if I had to guess, it could mean vorne, mitte, rechts or front, middle right in English.

[Legoman]

Does your car have front sensors too? While you don't get a code, Autologic does say VMR. Not a BMW abbreviation but if I had to guess, it could mean vorne, mitte, rechts or front, middle right in English.

Yes it has four tranducers in both the front and rear bumpers. All the front ones appear healthy though. They fire off the warning gong when you wave something in front of each of them.

[whiskychaser]

Did a bit more digging and it seems my guess that VMR means front, middle, right may well be correct. I get the occasional fault code with the PDCs on my E46 but they work fine. If you have a truly duff sensor, it will knock out the other 3 too. The worry of course is that you rely on them and end up reversing into a concrete post or something. I use DIS to diagnose the faults and that shows the actual distance from the bumper

[Legoman]

Did a bit more digging and it seems my guess that VMR means front, middle, right may well be correct. I get the occasional fault code with the PDCs on my E46 but they work fine. If you have a truly duff sensor, it will knock out the other 3 too.

That wasn't the case for me with the rear bumper. I had one completely dead transducer that did nothing with an obstacle wave in front of it, yet the other three on the same supply cable were all working normally.

I use DIS to diagnose the faults and that shows the actual distance from the bumper

What's DIS?

[shogun]

DIS is diagnostic/testing/resetting ,see http://bmwdis.com/ for more info.

[Legoman]

DIS is diagnostic/testing/resetting ,see http://bmwdis.com/ for more info.

Thanks for that. This looks like something I need. It looks like the latest version of this software v57 is only compatible with BMW Models manufactured between 1996 and 03/2009 so, I've found an old copy of the previous generation GT1 software called v52 with DIS v55, TIS 2007 + INPA 5.02 +VMware 6.5 instead. That DIS page seems to claim compatibility with vehicles as old as E28/E24 as well. If I were to buy the recommended ADS interface for use on my E32 and I also already possess a large round serial ADS (for E32) to small round serial ADS (for E28/E24) adaptor plug, then am I right in believing that with the software (currently downloading), a suitable laptop (already in possession) & the ADS interface cable (need to buy), I would then have everything I need to be able to clear these error codes on all my E32/E28/E24 cars myself?

In the meantime, I'm going to remove the front bumper now and swap the PDC sensors in it left <-> right and see if it makes any difference to the error code acronym into something roughly Germanic for Front, Middle, Left instead.

[whiskychaser]

If you are looking at getting an interface, consider one which does both ADS and OBD. Mine has a simple throw switch on it plus you run a tiny program so the software knows which system it is talking to. I have been running DIS v44 for about ten years and never had an issue with it. I know I can run a diagnostic on anything from 1989 to 2005 as I have done it. It lists the E24 and E28 but I have never tried so cannot confirm that.

Admire your persistence. I would not be removing the back bumper for what I think is a spurious fault. Still, it is my fault if I back into something

[Legoman]

If you are looking at getting an interface, consider one which does both ADS and OBD.

Thanks for your suggestion. I will look for that now I know such a thing exists.

Admire your persistence. I would not be removing the back bumper for what I think is a spurious fault. Still, it is my fault if I back into something

True, but it was really time for the rear bumper to come off anyway if only to clean out all the trapped leaf litter and give it a proper inside-out tizzy up. I inspected and cleaned up the rubber seal, resealed the cable entries through the rear sheet metal for the PDC + tow hitch cabling + reattached some of the spring clips holding the cabling that had fallen free of where they should be while I was in there too, so it wasn't just about replacing a single transducer.