[Boony]

Hey guys, I seem to have lost access to the OBD II port on my 07 e90 n54, build date 02/07; all of a sudden it has stopped working directly after flashing MHD v9. I hope someone can help me gain insight in diagnosing the issue.

Connectivity seems to return for a short while only after I take the negative terminal off of my battery for around 10 minutes and reinstalling it. Leaving the car overnight and coming back to it the next day, I find that it reverts back to the inability to connect.


The car runs perfectly fine and solid on e50. The car is FBO+inlets+walbro 450, xhp stage 3 flashed. No misfires, no issues mechanically. 110k miles.
The alternator is original, and when I do check voltages after the battery reset via MHD app, it reads 14.25v when car is on, 12.23V when car is off and ignition on.

The issue originally started DIRECTLY after I flashed MHD V9 e50 Stage 2+; a day before this instance of flashing, I installed a Stage 2 fuel pump successfully with no issues to the MHD connectivity using the monitor to observe LPFP pressures. 1 month before all of this I installed and properly coded a brand new 90Ah AGM battery via NCSExpert.


With the exception of a very odd issue everything else is running solid, I am only receiving an intermittent LEFT FOG LIGHT error. Once I drive the car the light issue resolves, both fog lights DO work, and the error goes away. I think this **might** be related, maybe the fog light is on the same harness as the OBD and its being under-powered? I also have an aftermarket amp, and aftermarket LOC (LC2i) installed. The subwoofer works however activates only at a higher volume thresholds now. This could also be related to the harnesses that the LOC is connected to? Maybe these harnesses are receiving less power overall? This makes less sense to me since the battery is brand new and healthy.

I have checked fuse 58 (cluster + OBD fuse) behind my glove box and it is good. I also replaced the fuse just to test, and there is no change to my issue. No other lights on dash, everything on dash works. All stock electrical systems work perfectly fine from windows to the radio and navi. The OBD port looks fine, no pins pushed back or anything. My cable is installed with an OBD flush adapter within the dash so it never gets removed back and forth. I also took out the glove box and removed the junction box to check for water ingress, everything looks perfectly normal and dry. All fuses look fine. Reinstalled JB and reset battery, deleted all codes via mhd. Problem returns overnight.



Research throughout the forums has me directed at the JBE (Junction box electronics module)
I already have sourced a used one on eBay, (JBBE my car is K-Line) and it is on the way.

I have not been able to try a different cable. I will order one and see if that resolves any issues as well...however I don't think its the cable as after doing the battery reset the connectivity returns normally without me touching anything. I have also re-flashed the car while I had the access back to MHD e50 V8. This has not fixed the issue.


I know this was a long post, however I feel as if stating any hunch or possible relation could properly give better insight. If anyone can give me any further info/methods to check it would be great. I have BMW TOOLS + ISTA installed so I can definitely use them if someone gives me a little more direction. Thanks!

[Chris@VargasTurboTech]

I have occasionally had connection issues/weird things. Charge the battery, reflash your current map and see what happens.

Chris