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+---- Thread: Help diagnosing intermittent electrical faults (/showthread.php?tid=70398)
Help diagnosing intermittent electrical faults - Fractals - 17-10-2022
Hi all! I'm having some intermittent issues with my 2018 G30 540i xDrive. Can anyone help take a look?
Two weeks ago, I was driving on the highway cruising at about 80mph (130km/h) when all of a sudden, a bunch of errors popped up on the dash. The errors were mostly related to drivetrain malfunction and chassis stabilization. The car also went into limp mode (stuck in gear and engine wouldn't rev past ~3k rpm). I pulled over to a gas station and turned the car off. Upon turning it back on again, all of the errors were gone, and the car was 100% functional.
I had my laptop with me, so I scanned the car with ISTA. The below errors are what came up. Looks to mainly involve the DSC and DME. Mostly signal invalid errors. Test plan also stated these errors were "consequential faults" and thus no test plan/diagnosis was possible.
After the previous incident, I drove the car for a further ~1000mi (~1600km) with no further issues. That is, until a few days ago when the issue popped up again. This time, I was on the return leg of a ~350mi (~560km) trip. I was pulling into a gas station when all of a sudden, the same drivetrain/chassis stabilization errors popped up again. Looks to be similar faults. Anyone seen something similar or have any leads? Thanks!
RE: Help diagnosing intermittent electrical faults - willisodhiambo - 18-10-2022
Something is happening with the dsc and it is losing communication with the rest of the car. Maybe check the plug and also voltage supply to it as a start. Call up ecu functions and run through all the sensors. Such intermittent faults can be very difficult to diagnose.
RE: Help diagnosing intermittent electrical faults - Node - 18-10-2022
NOT with the rest of a car only. It is losing connection INSIDE of it too - fault 48086C is fully internal.
I would check whether underbody panel covering DSC is not broken and whether DSC is not wet. Otherwise, DSC itself could be on its way out
Did you drive over puddles when these happened?
RE: Help diagnosing intermittent electrical faults - Fractals - 18-10-2022
Thanks guys!
I do think too it has something to do with DSC. I haven't had the chance yet to put the car up in the air. Cursory glance shows panel is still in place and seemingly undamaged. I'll do a more thorough inspection of the DSC this weekend when I have the chance.
For the first occurrence, I was driving through the CA Central Valley (dry/desert-like climate) on I-5 heading south from SF to LA. Time of incident was around 14:00. It was around here (Google Maps link). Temperature was ~88F (~31C) and weather was dry/relatively clear. Road condition was smooth and no water/debris on roadway. Speed was ~80mph (~130km/h).
Second occurrence also happened in the CA Central Valley in the evening (18:00) around (Google Maps link). Temperature was ~84F (~29C) and weather was dry/relatively clear. Road condition was bumpy right before second incident occurred, but no water/debris on roadway. Speed was ~10mph (~16km/h). I wonder if having the error appear right after driving over the rough/bumpy pavement is indicative of a loose connection internal to the DSC?
RE: Help diagnosing intermittent electrical faults - StarmanBL - 19-10-2022
(17-10-2022, 21:33 PM) Fractals Wrote: Hi all! I'm having some intermittent issues with my 2018 G30 540i xDrive. Can anyone help take a look?
Two weeks ago, I was driving on the highway cruising at about 80mph (130km/h) when all of a sudden, a bunch of errors popped up on the dash. The errors were mostly related to drivetrain malfunction and chassis stabilization. The car also went into limp mode (stuck in gear and engine wouldn't rev past ~3k rpm). I pulled over to a gas station and turned the car off. Upon turning it back on again, all of the errors were gone, and the car was 100% functional.
I had my laptop with me, so I scanned the car with ISTA. The below errors are what came up. Looks to mainly involve the DSC and DME. Mostly signal invalid errors. Test plan also stated these errors were "consequential faults" and thus no test plan/diagnosis was possible.
After the previous incident, I drove the car for a further ~1000mi (~1600km) with no further issues. That is, until a few days ago when the issue popped up again. This time, I was on the return leg of a ~350mi (~560km) trip. I was pulling into a gas station when all of a sudden, the same drivetrain/chassis stabilization errors popped up again. Looks to be similar faults. Anyone seen something similar or have any leads? Thanks!
Since you have ISTA, calculate test plan and go from there... D42C67 is main error and start from there. Is there any retrofits in car? Check connections on BDC, DSC anything you maybe work on before, if you done any retrofit on car check that first, also, if you done any FDL coding etc, check that to... But ISTA will calculate test plan and I would start from there..
regards