Drivetrain Malfunction / 120308: 0X120308 BOOST PRESSURE CONTROL error code...

[miltolam]

roup, I have a 2011 F10 xDrive. Just recently while cruising on the highway in Sport mode, I got the "Drivetrain malfunction" message and the car goes into limp mode. I did a Bimmerlink scan and this is what I'm getting for info memory (see screenshot of report in photo below). I'm guessing that the motor error (120308: 0X120308 BOOST PRESSURE CONTROL, PLAUSIBILITY: PRESSURE TOO LOW) pertains to this problem.

Can anybody give me more information regarding this issue? Is this common for the N55 and is there a way to better diagnose the problem before I take it to the stealership? And lastly, until I am able to get it checked out, if I keep it in Normal mode (2011 doesn't have "Comfort Mode") will I be doing any disservice to the the car by driving it? Thank you in advance for all your help.

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[shadowpuck]

https://www.bimmerforums.com/forum/s...cal-Help-Forum

[bmwdirtracer]

The first place to start is having the intake system smoke tested with a professional smoke machine.

And, like shadowpuck, I do not like the term stealership either. It's highly disrespectful of the thousands of honest, highly qualified people who work at these tightly regulated businesses which follow a fair and straightforward business plan. Keep in mind that the dealerships are my "competition", because I work for an independent shop, but neither I, nor the majority of the guys on this forum, appreciate someone insinuating that dealerships or their employees are thieves.

[White94RX]

The most common causes of a boost pressure too low fault code is a broken charge pipe where it attaches to the throttle body, or a faulty boost pressure converter for the vacuum wastegate. BMW has stepped up and extended the warranty on the pressure converter for some vehicles. If you can post your last 7 digits of your VIN, I can check to see if your car has that coverage. I'm not saying that is the problem for sure, but it's one possible thing.

[bmwdirtracer]

The most common causes of a boost pressure too low fault code is a broken charge pipe where it attaches to the throttle body, or a faulty boost pressure converter for the vacuum wastegate. BMW has stepped up and extended the warranty on the pressure converter for some vehicles. If you can post your last 7 digits of your VIN, I can check to see if your car has that coverage. I'm not saying that is the problem for sure, but it's one possible thing.

Thank you, my friend....I'm always learning new things from you, and I very much appreciate that.

See what I mean, Miltolam? White 94RX is a factory/dealer Level 1 Master Tech, and he's here, sharing his wisdom, for free, with both you, and me. Now he's even offering to check whether you might be able to receive one of these potential repairs FOR FREE, at the business which you've just maligned.

I think it's time for you to stop using that term, don't you?

[White94RX]

I think it's time for you to stop using that term, don't you?

I agree. I hate it. Not all of us are crooks.

[miltolam]

Let me start off by first apologizing if anyone took offense. I sincerely meant no disrespect...Won’t happen again, promise!

@White94RX, the last 7 of my vin is C778996.

Just to give you all an update, I’ve driven from Philly to NYC 2 more times (104 miles each way) since this post and had the car in normal mode going to and sport coming from. In sport mode, I was anywhere from aggressive to easy on the gas, at around 75-90 mph...I did not get any drivetrain malf. message. Let me also add that when I did get the message, I did no get a SES light nor did it felt like it went into limp mode, although it said it did. Now I’m perplexed .


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[White94RX]

I checked your DCS warranty report, and your vehicle DOES NOT have the warranty extension on the pressure converter. So IF that is the problem, which I can't guarantee, then you're on the hook for the repairs.

I always tend to second guess myself, but I'm pretty certain your turbo is vacuum wastegate controlled and not electronically controlled. If it was electric wastegate actuated, then it wouldn't have this part.

[bmwdirtracer]

Ah, now we're talking MY language....White 94Rx caught me once telling someone to go check his vacuum lines when he had an electronic wastegate......SO, go have a really careful look at every single vacuum line on the passenger side of the engine. Broken hoses really hide themselves well, so don't make it a quick look: feel every single hose, especially down at the lower ends, where they get heat-toasted.

Russ, I can't tell you how glad I am that another tech got the N63 swap.....(I've got a lovely S38 M5 on a big project). He's SO bewildered, poor soul. I just can't tell you how easy my S62 looks these days! Who designed that turd N63?

[White94RX]

It's definitely a turd, but I've done so many, that I know my way around them all too well at this point. And with the new class action suit, it looks like I'm going to be replacing many of them. There's only a handful of guys here that don't mind doing engines. A good portion of the guys would rather pawn it off on someone else.

[bmwdirtracer]

I'm absolutely fine with engine replacements....but the N63's the ugliest SOB I've ever worked on. I know that familiarity with it would make me comfortable, but I'd rather rebuild S38's and S62's and S52's, one after another. The damned 63 k mile N63 with floppy t-chain is also leaking everything, everywhere. Four wheel drive makes it even uglier! (Yeah, okay, faster too)

A NEW class-action? Oh Boy, can I just send them off to you then?

[miltolam]

White94rx...Yes, it is a Vacuum Wastegate. Surprisingly, I’ve been to and from NYC twice including yesterday and that message has yet to reappear. It’s been a few weeks already. I’m wondering maybe the car was crying wolf; bad gas or something, idk.


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[White94RX]

Please no, I don't need any more N63's than I already have to deal with

It's possible that the pressure converter has an intermittent failure. Or it could be something with the vacuum line. The converter is nothing but a relay for the wastegate actuator. Vacuum comes in at all times from the valve cover. When you press on the gas pedal, the converter opens, and this vacuum is applied to the hose going to the wastegate to close it. Then you get boost. And when the DME detects the proper boost level based on your throttle input, it opens the wastegate to maintain boost, and not overboost.

[miltolam]

Hey guys, Just a follow up...Still no Drivetrain Malfunction message. I’m taking the car in to a local BMW/Mini specialized shop Monday to have them do what they call a “Post purchase inspection”. They will go through the car with a fine tooth comb and give me a detailed report on any present or impending issues the car might have.

On a separate note, we’ve been getting an abundance of rain in the northeast the last couple months. I’ve noticed that my driver side footwell has been damp on a few occasion. Doesn’t appear to be coming from the door. Just the floor on the rear driver side is damp. I briefly did some research and seen something trending on this subject in regards to a grommet attached to the firewall near the glove box that is the possible culprit. Does this sound familiar to anyone? Thx in advance.


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[bmwdirtracer]

I answered your other thread, regarding the leak....but no, a grommet near the glovebox did not put water in the rear driver's side footwell.

[White94RX]

Remove all the door panels and check the vapor barriers. Reseal or replace as necessary.

[F30 328i]

Hi guys I know it's an old thread but I have a f30 328i n20 and I've been getting
120308 low boost
130408 boost block
121533 boost low at motor stand
I've seen most ppl cars reset after turning off, my code goes away but as soon as you hit 2500 my cars code light up and limp mode if on sport mode it gives me the response it normally would have on normal and makes it to 3500 before codes light up. If on sport+ no difference as sport, just wondering if, I've visually checked pipes and can't see cracks or leaks, can't hear any hissing or abnormal sound's, but the charge pipe coming from intercooler to throttle body does have a little play, if a use a silicon hose and two clamps (assuming there's a leak) will this stop the leak? Also would a dv cause this and my fuel efficiency has dropped aswell maybe getting 300+ kl out of full tank usually get close to 500some advise pls. I've looked for normal vaccum lines but can't find any only this thic ones and my wastegate is electronic I'll try post a small video of it working and a picture of this vac valve I've been told to change but can't find it. Any advise would be greatly appreciated. Thanks you all.

[Dongotti]

Hey guys, Just a follow up...Still no Drivetrain Malfunction message. I’m taking the car in to a local BMW/Mini specialized shop Monday to have them do what they call a “Post purchase inspection”. They will go through the car with a fine tooth comb and give me a detailed report on any present or impending issues the car might have.

On a separate note, we’ve been getting an abundance of rain in the northeast the last couple months. I’ve noticed that my driver side footwell has been damp on a few occasion. Doesn’t appear to be coming from the door. Just the floor on the rear driver side is damp. I briefly did some research and seen something trending on this subject in regards to a grommet attached to the firewall near the glove box that is the possible culprit. Does this sound familiar to anyone? Thx in advance.


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I know this is a few years old but did you ever find a resolution to the low boost condition? I’m experiencing the same with no other associated codes.

120308: Boost pressure control, plausibility: pressure too low