[StormtrooperN55]

Car: 2011 335i N55 with 94k miles
Hi I'm having a weird issue with my car. I am getting error message on dash intermittentanly that says charging malfunction. The codes I got are
- DME active codes -
3446 - BSD, message; oil condition sensor: Missing.
378F - BSD, message; electric coolant pump: Missing.
3847 Generator, Kommunikation: Bus-Fehler
384A Generator, Plausibilität, elektrisch: berechnet
38A4 - BSD, message; intelligent battery sensor (IBS): Missing.
I don't know if its a coincidence but before I started having these issues. I changed my Vanos solenoids as preventative maintenance and to try to trace a rough idle. The Vanos I used to replace the original were Dorman brand and it caused the car to stutter while accelerating so I removed them and put the old ones back in. Ultimately the rough idle I traced back to the BMS Intake since it was also throwing codes for intake pressure to high. Putting the stock air box back on remedied the rough idle but now ever other day I get charging malfunction error mostly after driving around for more than 20 minutes or when the car warms up. Besides this my plugs are only a month old. Coils are less than year old.
Any help would be appreciated. Thank you.

[gbalthrop]

I have an N52KP and NOT N55, but my concept of MULTIPLE BSD Bus codes is that there is a wiring/ connector fault somewhere in the system. In other words, a SINGLE fault or bad connection is causing MULTIPLE Fault codes related to BSD connections at multiple components (OZS, IBS, Coolant Pump, Alternator) all of which are supposed to be connected to that Bus.

Here is the TIS circuit diagram for the BSD bus on your vehicle:
https://www.newtis.info/tisv2/a/en/e...ces/1VnXfV9T3f

Based upon the "history" you provide about the issue occurring after doing certain repairs, the likelihood is that something in those repairs pulled one of the BSD bus connectors loose, such as at the Alternator, near where you were working, or damaged a wire between connectors.

I would inspect ALL connections in the BSD bus, and if cleaning with Electronic Contact Cleaner does NOT correct the issue, then disconnect all connectors and test for (1) continuity or (2) short to ground in each of the wires in the Bus.

Please let us know what you find,
George

[StormtrooperN55]

Originally Posted by gbalthrop

I have an N52KP and NOT N55, but my concept of MULTIPLE BSD Bus codes is that there is a wiring/ connector fault somewhere in the system. In other words, a SINGLE fault or bad connection is causing MULTIPLE Fault codes related to BSD connections at multiple components (OZS, IBS, Coolant Pump, Alternator) all of which are supposed to be connected to that Bus.

Here is the TIS circuit diagram for the BSD bus on your vehicle:
https://www.newtis.info/tisv2/a/en/e...ces/1VnXfV9T3f

Based upon the "history" you provide about the issue occurring after doing certain repairs, the likelihood is that something in those repairs pulled one of the BSD bus connectors loose, such as at the Alternator, near where you were working, or damaged a wire between connectors.

I would inspect ALL connections in the BSD bus, and if cleaning with Electronic Contact Cleaner does NOT correct the issue, then disconnect all connectors and test for (1) continuity or (2) short to ground in each of the wires in the Bus.

Please let us know what you find,
George

Thanks for the info. I will go over it. Currently Im putting my old coils back on since i did some research early and some had these faults because of using Delphi coils or possible counterfeit Delphi coils.The only connecting Im worried about is there is one right in front of the lower vanos solenoid that was in the way unless you pulled the solenoid straight out on the position it was in. Not sure what that wire goes to but it seems intact.

[nsjames]

often the water pump electronics get wet and fail. Takes down the entire bus.

suspect you're doing a water pump soon.

[StormtrooperN55]

Originally Posted by nsjames

often the water pump electronics get wet and fail. Takes down the entire bus.

suspect you're doing a water pump soon.

Yea could be ill see if the codes return after the coil swap if not ill start looking into replacing the waterpump. I did a water pump bleed and it runs but it sounds like its grinding bearings inside. Doesnt sound normal..

[gbalthrop]

Originally Posted by nsjames

often the water pump electronics get wet and fail. Takes down the entire bus.

Does the N55 have a "part-plastic" coolant pump like the N54? If in fact a leaking pump body caused a short in Connector X6035 where the BSD Bus (Pin #2) was shorted to ground (Pin #4), wouldn't disconnecting that X6035 connector, drying it out, and clearing the codes restore normal operation without fault codes as far as IBS, OZS, & Alternator are concerned?

https://www.newtis.info/tisv2/a/en/e...oling/CkZZ9efB

Obviously do NOT want to run the engine for more than ~ one minute with NO power to coolant pump.

OP, don't know what you read the BSD codes with, but obviously it reads BMW FC, and I don't see ANY Coolant Pump codes. It could still be leaking, even though no speed deviation or shutdown codes, so that is one more thing to check.

George

[nsjames]

just disconnect the pump, clear the codes and see if the rest of the modules come back to talking. no need to even start the car.

if so, pump electronics are shitting the bed.

yes,pumps are the same.

3 Series
E90 / E91 / E92 / E93 (06-13) > 335i
E90 / E91 / E92 / E93 (06-13) > 335is
E90 / E91 / E92 / E93 (06-13) > 335xi

[StormtrooperN55]

Ok so I did a couple things. I checked out grounds and they were fine. I cleaned connectors for oil sensor and water pump. I read in the forums some had issue with Delphi OE coils. Although I had no issues with them for a year I dug up the old ones that the car had when I purchased it and decided to swap them back in. The Delphi coils that were OE looked different then the OEM ones. So far its been 3 days and those BSD codes have not returned yet. Looks like some people have had this issue with the OE delphi coils sending voltage spikes and for some it has fried the alternator. I hope mine was sparred but so far so good. Won't be convinced until it clear for another few weeks.

I apreciate all the help you guys have posted I will keep that in mind for future reference.

[GB-335xiCoupe]

I'm experiencing similar symptoms as in your original post... same error codes. Car is a 2011 e92 335xi, 206k miles with the N55 engine. I'm using MHD Stage 1.


However I noticed my OFHG is leaking and there is oil residue in several places on the engine and alternator, under the OFH, so I think either I have the ignition coil issue (these were recently changed from OE to Bavarian Autosport 5005), or the oil getting on and into the alternator has caused it to start failing.



What confuses me is the Alternator seems to be normal, based on multi-meter voltage testing under load, not under load, ground check and drain etc.


I've ordered a new OFHG and will replace it asap. I think I'll try to swap back the OE ignition coils first since this seems to be the easiest thing to try. Thanks for the posts. I think I'm headed down the right path. Any other suggestions? Is there an easy way to isolate the problem to the voltage regulator? I'd hate to replace a $400 alternator that is functioning properly.

[StormtrooperN55]

Thats great youre getting close. For me the issue never returned till this day when i went back to stock original coils. I probably need to replace them soon with oem. Hopefully your issue is the same and you avoid. Alternator replacement. Ive also heard a failing water pump can knock down that bus also. Alternator, waterpump, oil level sensor are all on that bus. I think bad coils jusy disrupt the electrical system altogether and sets off that bus triggering those codes.

[GB-335xiCoupe]

Originally Posted by StormtrooperN55

Thats great youre getting close. For me the issue never returned till this day when i went back to stock original coils. I probably need to replace them soon with oem. Hopefully your issue is the same and you avoid. Alternator replacement. Ive also heard a failing water pump can knock down that bus also. Alternator, waterpump, oil level sensor are all on that bus. I think bad coils jusy disrupt the electrical system altogether and sets off that bus triggering those codes.

I hope you are right. I'll know tomorrow when I swap them out. If it works, I'll post my findings in a week or so after driving.

[xxirish83x]

Any updates here dudes?

Having the same issues. Car has had a lot of parts within the last year and I’m beginning to lose my mind with it... considering selling it. I keep saying “well now it won’t break I just fixed x“ and something manages to break.

Within the last year I have replaced shocks, struts, full pads and rotors , full cooling system refresh w radiator, plugs, coils, high pressure fuel pump, Walnut blasted, intake manifold w pcv valve, oil pressure sensor, belts, o2 sensors, downpipe, fmic, and a starter. I’m bet I’m missing a thing or 2 as well.