[Scottycs19]

Hey Guys,

Just picked up my second X3 (2012 N55), I also have. F97 X3MC. Not much action on the X3 board, so I figured I would post here since it is the same engine. So far I love it and the only issue is the 101F01 code and a ever so slight idle miss occasionally. Drives great under load...

The last owner recently replaced the Valve Cover, HPFP, Throttle Body without success. It also has a recent Valve Cover Gasket replacement and walnut blast.

Based on videos I have seen, I put a match in front of the PCV diaphragm and saw no air being sucked in. No odd noises either. However upon removing the oil cap there is a decent amount of suction and you can hear it sucking the air in if you slowly open the cap. I looked & listened for vacuum leaks, but found nothing and given the cars performance under load, I don't suspect any.

I have also performed the adaption procedure here without any success. https://static.nhtsa.gov/odi/tsbs/20...63029-9999.pdf

Has anyone experienced this fault? Can anyone point me in the right direction?

Thanks!

[Scottycs19]

It would appear my manifold sensor is bad based on these readings.

[Scottycs19]

Swapped Map Sensors....no change. When running it appears the vacuum post throttle valve is 50 hpa lower. Reads the same when off.

When the tank ventilation valve is disconnected the code 101F01 is not present. However upon connection it appears again.

Back to square one to identify this code. Other than coding it out within a tune, any other ideas? The car runs great but I need to get it inspected!

Any help appreciated tracking this down!

[thejeremyman9]

Some difference like that is normal with the car running since one is after the throttle plate.

[Scottycs19]

You are correct. I confirmed they were the same when the engine is off meaning they were reading the correct values.

Originally Posted by thejeremyman9

Some difference like that is normal with the car running since one is after the throttle plate.

Happy to report I solved this code and reported 100 miles with no CEL.

The culprit was a bad MAF, even though the MAF did not throw a code itself. Looked good and I cleaned it, no change. After looking at the values, the air mass would range 8-22 kg/h. I figured this could not normal, and it wasn't. New $40 aftermarket MAF on Amazon no varies 13-14 kg/h at idle and the car runs much smoother!

[yupetc]

I am absolutely not planting a seed to rack your brain. But once you’ve exhausted all possibilities with no success of addressing the code, then resort to this nearly impossible possibility:

My version of the 101F01 happens when the motor has a combustion leak, or any leakge-caused incomplete combustion. I know this for a fact because during my build with forged internals, I accidentally missed installing the suspension/decoupling element on injector #6 cylinder. At first the motor ran fine for 3-4 months, but that injector port did finally give up and there is combustion blow-by coming up the injector port. I refer that as a combustion “wash-out”, borrowing physics nomenclature from the oilfield drilling industry. I learned all of this because I did have 101F01 which I also threw a lot of new parts onto addressing the issue before the port wash-out disaster. Then one day I receive another code and it’s something about incomplete combustion on cylinder 6. Then on the day of the limp mode failure codes pulled are the same with an addition of multiple misfires. During top end removal is when I found the witness marks of carbon-like trail of combustion blow-by around cylinder 6 injector port. At this point, the injector was no longer snug sitting in the port. If the T-bracket isn’t there to keep the injector held in place, this injector would have came up further and possibly bend or break the connected fuel line. By the time I got to this injector I was able to just take the blackened injector out without any effort at all. I later tried a repair using a TIME-Sert style kit which is available for the N55 head. It worked for about 3 months, then I started getting the same code again, 101F01. Without any reason to believe it could be due to this injector port again, I kept on driving while looking for other possibilities to throw new parts on the motor again. A month went by, I get a Christmas tree on dashboard along with limp mode during a road trip. Luckily I wasn’t far along the trip so I limped back on cylinders 1-4. 5,6 have been disabled during this limp mode. When I got home to look at #6 injector port I found a gasoline filled port 5 and 6. Also discovered and concluded that the time-sert port repair didn’t hold for long and it broke the injector and spilled gasoline all over the valve cover during that failure.

Anyway, got a new head installed, but a week into the new head, I get incomplete combustion codes for 5 and 6 cylinders, key here is that 101F01 is also tagging along the codes again. Just before I throw the white towel I quickly found out the corresponding spark plugs have some detached porcelain body, allowing combustion blow-by, this time, through the broken spark plug body. I replaced new spark plugs and new ignition coils. Apparently I’m to blame myself because I re-used the gasoline-drowned spark plugs from last disaster without paying attention.

Car’s been running strong and perfect till this day. No more codes.

Again, not trying to throw you into this chase of port wash-out possibility because there could be too many causals for the 101F01 code. Just know that my case did happen and thus it’s a possibility.

[GORDON.M3]

Originally Posted by Scottycs19

You are correct. I confirmed they were the same when the engine is off meaning they were reading the correct values.



Happy to report I solved this code and reported 100 miles with no CEL.

The culprit was a bad MAF, even though the MAF did not throw a code itself. Looked good and I cleaned it, no change. After looking at the values, the air mass would range 8-22 kg/h. I figured this could not normal, and it wasn't. New $40 aftermarket MAF on Amazon no varies 13-14 kg/h at idle and the car runs much smoother!

How's that MAF holding up? Still good no 101F01 code?