[Algold415]

@thewheelm4n

I feel your pain.. My 335d drives perfectly otherwise, it only triggers the 4580 when the RPMs drop to idle. I took it out yesterday for a long freeway cruise, and had the limp mode go on a couple times as the car was coasting down a hill, otherwise it ran like a champ.

I'm starting to think this might be some kind of electronic problem either with the DDE or the Fuel Control Module (16147229173) - see attached pic.

Yesterday, I used my Foxwell scanner and took a look at the 'Control values for speed control' of the LPFP. The actual speeds (in RPMs) jump all over the place from ~1600 to ~3500, which looks absolutely inconsistent. I wish I could post a video here, but I don't think it would attach, since it's a big sized file. I did the same test on my X5 35D, and although the RPMs jumped kind of inconsistently as well on the scanner, it wasn't such an extreme deviation, going from ~1800 to 3500 rpms up and down like the 335d.. I'm not sure if perhaps the scanner is too slow or not showing the proper values but it definitely seems like something to look into.

Also, another thing I noticed and will attempt to check, the Fuel sending unit(under the back seat, driver's side - part 16117190947) has the fuel return hose that has a 'pressure relief valve' on the end of it. I'm wondering if these valves can fail or get clogged up and cause the return line to be backed up? - (see attached pic).

Please keep me posted if you make any progress on your end!