BimmerFest BMW Forum banner

1 - 20 of 32 Posts

·
Registered
Joined
·
1,065 Posts
Discussion Starter #1
Must have missed this one because I was surprised when my SA said that besides the airbag recall, my 2012 X5 diesel has also an open MAF sensor recall. Has anybody had this recall done on their diesel?
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
Joined
·
18,405 Posts

·
Registered
Joined
·
1,065 Posts
Discussion Starter #3
Doug, thanks for the link. Put in my VIN and it only shows the airbag recall. Maybe MAF sensor replacement is a "non-safety" recall :dunno:
 

·
Resident Curmudgeon
Joined
·
23,393 Posts
It may be a 'service action' ...that isnt a 'recall' so it isnt published, mandated, etc etc
 

·
Registered
Joined
·
448 Posts
Hmm i had to change mine on my own last year, car is way out of warranty now but it has been changed once under warranty according to the records.
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
Joined
·
18,405 Posts
Doug, thanks for the link. Put in my VIN and it only shows the airbag recall. Maybe MAF sensor replacement is a "non-safety" recall
Ya gotta ask your SA, only he knows. You gotta be a bit skeptical when someone mumbles mumbo-jumbo jargon at you, stuff you've never heard before.

MAF replacement was a cure-all for early TDIs, one would unplug the MAF, and, if the car ran better, replace it. Mine went thirteen years on the original MAF.
 

·
Registered
Joined
·
1,250 Posts
Ya gotta ask your SA, only he knows. You gotta be a bit skeptical when someone mumbles mumbo-jumbo jargon at you, stuff you've never heard before.

MAF replacement was a cure-all for early TDIs, one would unplug the MAF, and, if the car ran better, replace it. Mine went thirteen years on the original MAF.
Unplugging the MAF on our diesels disables the EGR so it runs great until you get a CEL :).
 

·
retired engineer
Joined
·
27 Posts
I had this done in April as part of normal maintenance appointment. 2012 E70 Diesel
 

Attachments

·
Registered
Joined
·
1,292 Posts
This morning wife sent me a txt with a picture of the CEL asking what it was. I told her that the light informing you'll be spending more than $1,000 over the next 30 days... Great!!!

Since my day was ruined and the monthly budget was already down the toilet I invited her out to lunch and used Carly to check the code. Turns out is code 3FF1 which apparently has to do with the MAF. I vaguely remember a recall or something so came here (I've missed you guys, particularly ard and Mr Huffman...) and confirmed there was one. Called local BMW with the excuse of the airbag recall which I still have to do (but don't want to do on the passenger side since I'm scared of them breaking stuff...) and apparently doesn't apply to my 2009... The glimmer of hope went away while I was adjusting on the chair for the new hole in my pocket...

Well, to my surprise turns out that the MAF for a 35d p/n 13628509725 is a tad more than 20 bucks!!!! Yes, 20 dollars for a MAF, genuine BMW, from getBMWparts (BMW dealership in MD)... The mind just boggles...
 

·
Registered
Joined
·
1,250 Posts
That is a big price drop. I paid $200 for the Bosch one 2 years ago. The 335d tuners swear these slowly wear out and hurt performance. For that price I may as well change with every air filter :).

For anyone curious, you can pop off your engine cover and easily see the part number and date manufactured. If you are on one of the older part numbers, it makes sense to upgrade to the latest version of this part. The MAF really affects performance and fuel economy as well as EGR functionality.
 

·
Registered
Joined
·
1,292 Posts
I reset the code the other night and cleaned the MAF but the code came back. I've always been skeptical of the actual MAF being a culprit for MAF related codes but in this case it's the only code I get and the part has a history of failure. I was reading in RheinGOLD that apparently DPF regeneration is suspended when the code is stored so didn't want to just drive around with it...

Before ordering it online I called my local dealer just to check and turned out the list price from BMW is $33 and with the discount I get he was selling it for $27 so ended up buying one. But in any case, looks like that's the actual price from BMW which again is surprising given that in all my other cars the MAF was always a $250-$400 part...
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
Joined
·
18,405 Posts
I disbelieve that spray cleaning the MAF sensitive element will be effective.

I believe that it, the sensitive element, and the reference element, are very small thin film resistors that are heated and the air flow calculated by comparing the heating current. As the temperature goes up, due to low air velocity or thicker baked on thermal insulating layer, the voltage dropped across the resistor increases. The engine air filter allows hydrocarbon vapors to contact the heated sensitive element and bake onto its surface sufficiently thick to make the heating current implausible.
 

·
Registered
Joined
·
625 Posts
I reset the code the other night and cleaned the MAF but the code came back. I've always been skeptical of the actual MAF being a culprit for MAF related codes but in this case it's the only code I get and the part has a history of failure. I was reading in RheinGOLD that apparently DPF regeneration is suspended when the code is stored so didn't want to just drive around with it...

Before ordering it online I called my local dealer just to check and turned out the list price from BMW is $33 and with the discount I get he was selling it for $27 so ended up buying one. But in any case, looks like that's the actual price from BMW which again is surprising given that in all my other cars the MAF was always a $250-$400 part...
I had the MAF replaced in Oct 2016, I wasn't eligible for the warranty or recall on that piece, and it was $498 out of pocket. $30 for future piece of mind is easy mode.
 

·
Registered
Joined
·
874 Posts
So I ordered a MAF from getbmwparts, special shipping, I was all in $44. Popped it in when I got home and the Engine Malfunction light went out! The truck is running a lot better too! Amazing, I was dreading this repair! Next I have to clear the codes and get the DPF regenerated.
 

·
Registered
Joined
·
1,292 Posts
Well... Turns out that yet again a MAF code DOES NOT mean a bad MAF (unless I got a defective one...): turns out the code is back so I had to do some digging.

So first of all... Here's what the MAF is used for in our diesel (all sources are BMW litterature): "The HFM 6.4 measures the air mass intake within very close tolerances so as to permit precise control of the exhaust gas recirculation as well as optimum configuration of the smoke limit. This is important for complying with current and future emission limits." and "The HFM 6 hot-film air mass meter is located downstream of the intake silencer and is fitted directly to its cover. The HFM measures the air mass taken in by the engine. This is used to record the actual air mass, which in turn is used to calculate the exhaust gas recirculation rate and the fuel limit volume. There is also an intake air temperature sensor located in the HFM housing. The temperature is evaluated by the HFM and sent to the DDE as a PWM signal." So, different role than a gasoline engine. Or at least it's used to affect AFR in a much less direct way...

Now with that being said the code 3FF1 I get is a failure to plausibility check: "the ratio of the calculated air mass to the measured air mass violates limit values that are dependent on the operating point". What that means is that the DDE calculates based on a series of parameters that air muss should be A but at the MAF is measures X*A and X is outside of a certain allowable range. Since I just replaced the geezless sensor I assume the measured value is correct so the problem is the calculated value.

A quick interject: the plausibility check is done occasionally under certain driving condition call it "cruising condition" which is "no sudden changes in torque demands"..

Now I have no freeken clue how the DDE calculates the air mass value but it's probably a condition of MAP reading, Wideband O2, EGR duty cycle and a bunch of other things, including, according to BMW litterature, the charge temperature sensor (i.e. the temperature sensor mounted in the charge pipe on the driver side, right before the elbow leading to the intake manifold): "The charge-air temperature sensor records the temperature of the compressed fresh air. It is located in the boost-pressure pipe, directly upstream of the throttle valve. The charge-air temperature is used as a substitute value for calculating the air mass. This is used to check the plausibility of the value of the HFM. If the HFM fails, the substitute value is used to calculate the fuel flow measurement and the EGR rate."

In essence there's a temperature sensor built into the HFM (a fancy name of the MAF) and another one on the charge side...

In any case. I removed the charge temperature sensor. It was lightly coated with oil so I gave it a clean, hopefully that was it (i.e. the oil coating was causing incorrect temperature readings... could be...)... Time will tell...

Just chronicling my adventure but who knows that someone out there have gone through similar endeavor
 
1 - 20 of 32 Posts
Top