Like the title says. I've been battling these two codes along with intermittent boost cuts with no apparent pattern or cause. When I originally got the code, I suspected my K&N intake finally gummed up my MAF sensor, so I replaced the K&N with an aFe dry filter. I cleaned the MAF sensor expecting that to solve it, but after a week the codes and boost cuts were back. Then, I purchased another MAF sensor from eBay that came off of a wrecked car: after a week or two, same codes and boost cuts.

At this point, I was pretty fed up, so I purchased a brand new MAF sensor and cable from a user on here. After installing the new MAF sensor and cable (last 6 inches of cable up to the plug), everything seemed normal until I lost boost and got the error codes again yesterday.

The boost cuts happen for 1 - 3 minutes and full boost resumes seemingly randomly after that amount of time. The car, otherwise, drives fantastically. Tons of power, smooth idles, brand new coil packs & plugs, everything. My MINI dealership drove it for a day and the only info they had for me was that "the car is definitely faster than stock." That's it.

Anyone have any ideas what this could be? It's extremely frustrating when you lost all boost at random times during the day.

Thanks!

 

During the boost cut, do you have clouds of smoke coming from the tailpipe? Cause I was having the same p115c code and boost cut with a huge black cloud of smoke. It would last a second or 2 and then everything would be fine again. I have seen people spend thousands of dollars trying to fix this problem. I've seen simple fixes of just using maf cleaner working for some. Then people replacing the actual maf unit working. I've heard it was due to a vacuum leak somewhere. ..then replacing the valve cover...then it was carbon buildup. I personally did all 3 of those. Maf unit. ..walnut blasting and a brand new valve cover. Even replaced the filter like you did. None of that helped. Car seemed to run better after the valve cover was replaced but still had the code. I kinda believe its because of the aftermarket intake on the car. Have you tried putting the stock intake back on the car and clear the code to see if it comes back?

 

That's pretty much the exact opposite of what I was hoping to hear haha.

I have had clouds of smoke, but they were white and smelled odd. At the time, I was having misfire codes, though. New coil packs solved that problem.

I have the original intake but I'd need to grab a new filter. I'll try that first. I'd imagine I should try to put the original down pipe on shortly after to test that as well. This is pretty annoying. The car hasn't changed mod-wise in over a year and this just started recently.

 

Yeah I had black smoke and believe the walnut blasting cured that if my memory is right. Think I drove for about 3 months before I started seeing the code. On the other hand I also don't think the p115c is causing your boost cut issue cause I just kinda gave up on the code and drove with it for quite awhile without any kind of issues stemming from it.

 

Mine might be different then because I get the check engine light and codes thrown right as a I notice a boost cut. Usually the boost is at -2psi and will maybe get up to 2psi under acceleration during the cut.

 

Anyone else have any ideas of what this might be?

 

Did you ever figure this out? I am getting P115C along with P1497 and reduced power in the upper RPM ranges.

 

I haven't figured it out yet. I've had the car at a dealership twice and they want me to remove all the aftermarket parts before proceeding with diagnostics. I might just go to a tuning shop so I don't have to go through that entire hassle.

I hate driving around with a check engine light, but the car runs fine 85% of the time. Every once in a while, I get no boost. 30 seconds to a minute later and it's back to 19psi of boost and runs like an animal.

 

Thanks. Keep us updated, and I'll do the same. I am going to start with a walnut blasting as I'm at 72k miles and never done it.

 

Alright sounds good. I just had the walnut shell blasting done a few hundred miles ago along with a new thermostat housing and water pump. That's when the symptoms started, so who knows what's going on.

 

Wonder how you're doing with this. I have been on vacation for two weeks but right before leaving I finally had a chance to take a look at my Mini. Turns out the Turbo Inlet Hose had slipped off the turbo. Such a simple thing, and it was a quick fix. Hope you're having the same luck.

 

I haven't gotten back to the dealership yet. I have been slowly getting back to stock. First step was going back to the stock ECU map. It's weird because after an ECU reset, the car runs normally for 3-4 days and the boost cuts are kept to a minimum. The more I drive it, the more frequently the boost cuts happen.

 

Instead of going back to stock and taking it to a dealership, I ended up going to a tuning shop. They diagnosed a turbo failure within 30 minutes. With 90k miles on the odometer, it's not exactly surprising. If anyone reads this that has a turbo for sale, let me know!

 

Glad you got this taking care of... sucks your need to replace the turbo. Have you thought about upgrading to the JCW or K04 unit?

 

I have, although I'm not sure which to choose. From my initial research, I like the sound of the JM40 hybrid and I haven't found anywhere to get a JCW turbo yet. My only restriction is that I don't want a wave of headaches if I replace the turbo with something that's completely different from stock.

 

Any update ragingMINI? I got the P115c code on my 08' Clubman S with 86,000 miles on it. I reset it and it comes on in about 5 minuets. Had the code for about a year, sometime after I put an Alta CAI on.

 

The Alta intakes are notorious for coming loose at the intake pipe at the air filter after sometime, I have heard they don't fit very well at all. Tons of threads and posts on these intakes coming loose and poor fit.

 

I just wanted to update this thread to let everyone know that this was caused by a failing throttle body. My dealership service center said they've seen a few 08-09 models throwing MAF sensor codes that ended up being throttle bodies. Sure enough, after replacing mine, everything seems normal again.

 

Yes, I have seen the throttle body tied to a P115C fault, which you can see from another thread HERE. A faulty throttle body can cause a number of problems, from a check engine light to a rough or surging idle coupled with P115C. For anyone else that may need one we have them HERE. We also have a DIY at that link at the "tech info" tab at the top under R56 Articles > Fuel Injection for anyone who needs help tackling the replacement themselves. Glad this resolved your issue and thanks for the update.