INPA error code 115 Hot film air mass meter - MAF failure?

[Spirit Force]

Hi,
my 540i stalled on thursday on freeway ramp. It started imidiately, but it stalled after I turned off the freeway on stopped on traffic lights. After that is stalled or almost stalled at every set of lights. I got the following error code with INPA:
115 Hot film air mass meter
Error frequency : 1 Logistic counter: 40
Engine speed 1480.00 /min
Intake air temperature 17.25 Grd C
angle DK oriented to DK-at stop 5.88 %
DK ADC HFM 1.00 V
Error currently available -- -- -- -- -- -- -- --
voltage value to low current,
-- -- --
voltage value to low Initial,
-- --
E-Flag debounce
CARB debounce
SCATT-active

So should I do some diagnostics on it or just replace it?

[Cereal]

You familiar with the unlocking of the obc?

Try test 4... Open that up and wind out some gears at wot. If you see a value at 85ish or higher maf seems to be functioning properly.

I just got same code as you last week and my maf wasn't registering the proper value. I popped in my spare and all better.

[Spirit Force]

DIS doesn't seem to have a test for MAF, it has for some models but apparently not for M62tu. So I did try the OBC test 4. In first and second I got ~112 l/h, but on third only under 60 l/h. Car isin't stalling anymore because it's idling at ~750 rpm (the same RPM as if you had A/C on).

[m5hoot]

DIS doesn't seem to have a test for MAF, it has for some models but apparently not for M62tu. So I did try the OBC test 4. In first and second I got ~112 l/h, but on third only under 60 l/h. Car isin't stalling anymore because it's idling at ~750 rpm (the same RPM as if you had A/C on).

Integral to the MAF sensor is a very fine wire- a high note piano wire, if you will. That wire gets heated to red hot once every drive cycle (I believe) to burn-off any dirt, gunk, or atmospheric contaminants that may tend to collect on this wire while driving or over time. This wire must remain absolutely pristine as it is the vibration or flutter of air passing that the *usually clean* wire that senses the air flow to your throttle body. Constant heating and cooling of this wire CAN cause it to break, thus setting the error. If the wire breaks, (you really can't see it unless you were to carefully cut open the sensor) the sensor is completely useless and unable to use that wire to gauge how much air is coming in that needs fuel to burn properly. Get new or used. No coding. I have an original, good Bosch from my M5, but not sure what you are driving...I forgot to look! That explains you error however. UPDATE: My sensor fits your car. PM me if interested.

[Cereal]

I didn't think m5 and 540I were the same?

Anyways, your obc readings are much higher than any others I have seen. Most m62tus I thought were in the 85-90 range new... That's what both my MAFs tell me
S62 in the 140 range

I'm starting to think your meter is faulty. You can order a Volkswagen part for our cars... It's around 90$

[m5hoot]

I didn't think m5 and 540I were the same?

Anyways, your obc readings are much higher than any others I have seen. Most m62tus I thought were in the 85-90 range new... That's what both my MAFs tell me
S62 in the 140 range

I'm starting to think your meter is faulty. You can order a Volkswagen part for our cars... It's around 90$

Admittedly, it has been a while since I looked, but I had a 2000 M5 and a 2000 540i and I believe they were the same. M5 has 2 of course. I have used both M5 sensors in my 2002 540 w/o issue. I find gas mileage to be the same using any of the 3 I have and to me, that is the affirmation I need. Car can not run richer or leaner and get same gas mileage.

[Cereal]

Good to know.. I didn't doubt you, just didn't know.

I'm trying to help diagnose a local m5 with bad MAFs and I think a vacuum leak so now I know I can try to swap mine to check.

[Spirit Force]

Integral to the MAF sensor is a very fine wire- a high note piano wire, if you will. That wire gets heated to red hot once every drive cycle (I believe) to burn-off any dirt, gunk, or atmospheric contaminants that may tend to collect on this wire while driving or over time. This wire must remain absolutely pristine as it is the vibration or flutter of air passing that the *usually clean* wire that senses the air flow to your throttle body. Constant heating and cooling of this wire CAN cause it to break, thus setting the error. If the wire breaks, (you really can't see it unless you were to carefully cut open the sensor) the sensor is completely useless and unable to use that wire to gauge how much air is coming in that needs fuel to burn properly. Get new or used. No coding. I have an original, good Bosch from my M5, but not sure what you are driving...I forgot to look! That explains you error however. UPDATE: My sensor fits your car. PM me if interested.

Thanks for the offer, but shipping to here would be way too expensive. I'm thinking about going the VW route. It's not exactly the same part, but close enough for it to work. According to 540iman it causes the engine to run 3-4% richer, which the O2 should correct.

http://www.bimmerforums.com/forum/sh...5#post11761845

[Spirit Force]

Installed the correct Bosch MAF for 540, because the price difference wasn't too big and it's running as it should, so problem solved.