[chrisbacha]

I have a BMW 325i with the n52 engine I'm getting a code for air mass metre signal 2d0f. when you start the car on a cold start and you press on the brake pedal the RPMs go up and down between 600 to 1000 rpm once the car is warmed up pressing the brake does not affect the rpm also the car doesn't want to start in temperature bellow -5 Which I assume is because of the the code

I have also replaced the MAF sensor and that did not solve the issue
and the engine does have an oil pan leak

any help would be appreciated

[Efthreeoh]

Not a lot of historical information to go from.

Did you check to see if the MAF is actually plugged in? Also, the engine may have a vacuum leak somewhere. Or the intake boot could be cracked.

[marvinstockman]

As above, and also you can clean you MAF with special MAF/Sensor cleaner from parts store.

[gbalthrop]

Originally Posted by chrisbacha

...325i with the n52 engine I'm getting a code for air mass metre signal 2d0f...

Here is the BMW Fault Code Lookup Definition for "2D0F", and the Fault Information Link:
N52 | P0102 | 2D0F | DME: Air-mass sensor, signal | MSV70
N52 | P0103 | 2D0F | DME: Air-mass sensor, signal | MSV70
http://www.bmwfault.codes/XMLDiagVie...kANgA1ADAANAA=

If you had INPA or ISTA, or other BMW-specific Scan Tool, it should tell you if signal is HIGH or LOW. If you don't have that, just get code read by any generic P-code reader, and it would show ONE of the following:

Bentley provides the following Definitions for P0102 & P0103:
P0102 | Mass or Volume Air Flow Circuit Low Input
P0103 | Mass or Volume Air Flow Circuit High Input

If you could get a generic P-code readout (either P0102 OR P0103, but NOT BOTH ;-) we would have a better idea if signal is High or Low. Either way, I would examine and electrically test the wiring & connector to the MAF. That code suggests there is a wiring fault, so test for voltage at Pin #3 of Connector X6207 at the MAF, and if NONE, then check F03 in the E-box. Here are the TIS Air Supply Circuit, MAF "Installation Location", and X6207 "Connector View":
https://www.newtis.info/tisv2/a/en/e...supply/p2Ru7TJ
https://www.newtis.info/tisv2/a/en/e90-325i-lim/SB2ajn6
https://www.newtis.info/tisv2/a/en/e...i-lim/HROdZZ4V

Please let us know what you find,
George

[chrisbacha]

I turn the vehicle on and tested the maf plug and I was getting 5 volts on two prongs and 14 one I then ran a traditional scanner and got a P0102  – Mass or Volume Air Flow Circuit Low Input. which I'm assuming is coming from a vacuum leak from one of the hoses but I'm running the engine and spraying brake cleaner on all the hoses and I'm not getting any rpm change is there any areas on the n52 that commonly leak ?

[NicoSuave]

Sounds like a vacuum leak

[E90_slides]

Originally Posted by chrisbacha

I turn the vehicle on and tested the maf plug and I was getting 5 volts on two prongs and 14 one I then ran a traditional scanner and got a P0102 – Mass or Volume Air Flow Circuit Low Input. which I'm assuming is coming from a vacuum leak from one of the hoses but I'm running the engine and spraying brake cleaner on all the hoses and I'm not getting any rpm change is there any areas on the n52 that commonly leak ?

Did you ever get this figured out? 2006 330i 6MT :

I replaced ccv and all hoses that are under vacuum, got the engine vac/smoke tested and zero leaks. They even tested the brake booster to see if it held vacuum and it did, held even at 15psi. My shop specializes in bmw Bentley and mini (ACR Motors Las Vegas) and they’re at a loss. I get no SEL, zero codes inpa.
Car runs real rough on cold start, almost bogs and dies, rpm’s jump up over 1k and then settles around 700 warms up and idle is fine engine doesn’t shake.

I’ve tested opening the oil filler cap while engine is running and no change, no blow by, and the suction created on my palm is moderate and feels right engine does not die or change in idle.
Have also drowned the known vacuum leak locations and hoses with carb cleaner while engine was running to see if idle changed but no effect.
I only get 20mpg highway/city driving.
I bought new upstream o2 sensors as well but have yet to install them since I’m not getting any codes I’m doubtful the o2’s are bad.
I can hear while I drive what sounds like air being sucked into a straw start around 2k rpm and seems to either vanish or get drowned out by the engine around 5k rpm.

So maybe there IS a vacuum leak but the techs are too scared of increasing the psi of smoke tester to prevent damage to other seals and in doing so can’t replicate the vacuum leak due to not enough psi applied to the head? I’ve been trying to find this problem for 10k miles now. The engine is definitely running rich my exhaust tip is always black.

Could this be an exhaust leak upstream of upstream o2s?
What is the safe limit of psi when conducting a vacuum/smoke test?
I have inpa and ista to read live data but I’m not too familiar with what is within spec. I’ll have to learn that and come back with my findings.