2014 328D Drivetrain Malfunction with 249300

[bmw chris]

Hey guys hoping some is familiar with the N47 diesels, girlfriends 14' 328D died the other day with Drivetrain malfunction. Now that I have the tool to actually check it only code present is 249300 - Rail Pressure too Low.

From searching have gotten mixed feedback on whether this is a supply pump failure or the HPFP failed. Anyone familiar with them that can point me in the right direction?

Apologies for the poor video quality my phone wouldnt focus, but shows the live data stream as the car turns over.



Thanks

[White94RX]

I would say it could be the HPFP. But we have seen several diesels that have gotten metal debris or shavings in the systems, necessitating the replacement of every single item in the system. But usually those cars set faults for injectors as well. BMW always has us remove the volume control valve from the pump and inspect it for "swarf" as they call it.

I haven't seen too many diesels with rail pressure too low fault codes. Don't think I've seen it at all really. Dumb question, but she didn't run out of fuel, did she?

[bmw chris]

It is showing 2/3 tank. My first suspicion was the supply pump, given her habit of running to very empty before she gets fuel. But after doing some reading it seemed more likely the HPFP.

Is the volume control valve the star bolt right on the middle of the pump?

Thanks!

[328 Power 04]

Were any of the last fillups at a lower quality station? Water contamination of the diesel is the #1 reason these fail. 2nd is incorrect filling with gasoline or sometimes adblue/diesel exhaust fluid into the fuel tank.


Insurance can cover the damage from water at a diesel station, but you may also see if the BMW extended HPFP warranty will cover it too.

[bmw chris]

I can confirm but since we are all working from home she only stops at 1 or 2 stations. Wouldnt rule it out but wouldnt necessarily head down that road either. I fussed at her enough that she quit stopping at random stations.

[White94RX]

If I recall, there are two T20 torx screws holding the volume control valve. I can't really picture it at the moment, it's been awhile since I did one. But BMW always has us remove it and take pics of the screen and the bore it sits in. If you find any particles or contaminants, you're screwed. Lol. Hope that's not the case.

Sent from my Pixel 5 using Tapatalk

[bmw chris]

Thanks guys, I will check that out. Was going to pull the supply pump and look for contaminants in the tank as well.

[wjb21ndtown]

Thanks guys, I will check that out. Was going to pull the supply pump and look for contaminants in the tank as well.

Just stating the obvious, but have you tried a new fuel filter? (and possibly cutting open your old filter) For $10, it may be worth a go. I believe BMW recommends changing them every 60k or so.