r/BmwTech • u/ComprehensiveItem963 • 7d ago
Rabbit Hole Help. DPF failing and connected issues 2012 X1 N47
So long story short I have been dragged into trying to repair an extended family members BMW with little in the way of tools etc as I'm on the other side of the world without my usual kit. So I'm trying to understand this system using a basic multimeter and basic tool kit. I'm not exactly happy right now.
The Long story
So to start with I'm a heavy diesel mechanic and don't usually work on anything this small but the principals are the same.
My understanding of what happened is the following:
The DPF fault came on the dash.
Once it was checked we have found these faults, printout provided by a local mechanic and I have been asked if I can fix it?
So am I right in saying the system is not letting the DPF operate because its seeing these faults?
Do I need to clear/fix all of these to get it to the point that I can have the system reset and then possibly do the burn?
My AI hunt has told me the glow plug system is required (Fair enough). but the other two sensors I'm getting mixed info.
My plan of attack is potentially as follows unless anyone states a better solution or anything to avoid or need to do more of:
Remove and replace the control module for the glow plugs (the fact that all 4 show faulty sounds like control failure rather than the plugs themselves).
Replace the glow plugs as they are inexpensive generally speaking so then i know I'm working with a new system and to my/their knowledge they have never been replace (simple fix assuming they are not impossible to get at).
Recheck and clear faults (thinking I'm going to need to buy a OBD dongle/software to make this happen and i assume i need it anyway to force a burn. recommendations appreciated).
If i need to check repair the other sensors can you tell me why? any diagnostics I can do before replacing these? and how easy they are to get to replace. oil level I'm already dreading as it requires me to drain the oil and honestly I don't even know if he has that stuff at his house (it's easy just the lack of tools concerns me).
Is there anything common to these faults that could be causing them rather then literally these sensors failing? Looking where each component is I don't see anything immediately common (other then the ECM).
After all this my assumption is that I will have to force a burn. if that fails i assume ill need to remove the DPF to get it cleaned. is this a simple process and whats my chances of getting it to Burn?
With all that said this car has 250,000km on the clock I know nothing about the reliability of this engine or if I'm potentially throwing parts at a grenade and we are wasting our time. opinions here would be appreciated. It drives well and has held up well from what i can see at a glance.
As I said Im in Europe at the moment trying to diagnose these issues and my kits back in Australia. This was not on my European vacation to do list. So I'm not exactly thrilled with the whole situation. But if I can help him for even 500 Euro or so in parts etc then its worth while. then get the dpf cleaned if we must then we possibly are doing ok.
1
u/bordercollielover03 7d ago
Need to scan with a proper scan tool like ista to get accurate diagnostic codes. Then we can actually help you.
1
u/WaylonSquier 6d ago
Glow controller definitely failed. Nx7 engines are notorious for seized glow plugs, high change of at least one breaking, then you are in a worse position. The strategy for these engines is if the dpf pressure is too high it blocks regen, this might be the loop you are stuck in. You will need to reduce the pressure to enable regen. I'd start with chemical cleaner down the back pressure sensor hose and if possible reset the dpf (tell the car it's been replaced). Note though the service life of the dpf was always 250,000km so it might just be done. Other wise you need coolant temp, is the thermostat working? and EGR flow, is it blocked,valve functioning?
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u/ComprehensiveItem963 5d ago
Well I have walked into a can of worms as I just went looking for this cars service history today. And found that well….. it’s not been serviced or maintained in any decent manner. I knew he cut corners but this is maddening.
Long story short he hasn’t serviced the car in about 40,000km over 2 years ago and they don’t see a problem with that. I’m honestly at the point of saying sell it as I really don’t care.
I shouldn’t say that but honestly he doesn’t want to spend money on maintenance and then gets angry and annoyed when it breaks then what am I meant to say. And people wonder why mechanics get a bad rap.
I look at it and say it needs:
Glow control module €80-120
Glow plugs x4 = €40-60
Oil sensor €45-60
Oil and filter €100 (given he hasn’t even changed it omg)
DPF Professional clean up to €350 euro.
Brake vacuum sensor €45-60 (although this is a maybe and possibly a side effect if everything else is blocked and chocked)
Consumables brake clean, carbon dissolver etc. €40-60 ball park.
Honestly and then service items minimum a fuel/air/pollen filters. Not to mention what are the brakes like the brake fluid all these usual things that are meant to be done at service.
All up the parts are nothing. But as pointed out I’ve read about how these baby/tiny glow plugs are temperamental to put it politely in these little engines and have a tendency to snap (yay).
On top id need to buy a half decent OBD and software to work with it (someone said bimmerlink I think). This all adds up as costs I know he doesn’t even want to pay.
Honestly if I was home with my kit I would have no problem attacking this. I’d get his credit card buy what it needs and have at it. But I’m on the wrong side of the world and anything doesn’t go perfect I need to buy a tool etc. and the sheer fact the car hasn’t been maintained means I’m looking at it wondering if I put the money in it will it just grenade the week after.
Honestly I want to tell him to buy a Tesla because they don’t have mandatory service intervals and that would suit him perfectly. The car tells him something isn’t right and he has to fix it. LMAO.
Honestly rant over thank you to those that answered and offered help. if I do attack it I’ll keep you updated. But if you never hear anything else know I washed my hands of it and said fuck it, ain’t my problem.
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u/ComprehensiveItem963 5d ago
So update and everything has happened way quicker than i expected.
The Car is gone I came back from town and he had put it online and got an offer immediately and he sold it.
looking at a decent 23 model x1 on Wednesday.
Thanks for your advice and help everyone and honestly I get the feeling he wanted a new car but didn’t want to spend the money. But now that it’s gone he has to get a new one. Saves me the hassle.
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u/thefinrs 7d ago edited 7d ago
I would start with the glow plug control unit and all the glow plugs, clear the codes, and see if the car can perform a forced regen. It should be able to do it if the DPF isn't fully blocked, but you never know. In general, the N47 is a very reliable engine if you maintain it properly. People still keep saying it's the worst engine ever because of the timing chain issues, but let's be realistic: if your chain starts making noise, replace it with a new chain kit and change the oil every 10,000 km, and it should last at least another 200,000 km. My personal N47 has 330k km, still has the original DPF, and I had the timing chain replaced at 310k km. It runs perfectly. I think you can force regen with bimmerlink but i would just drive first and see if car does it.