I have a problem with my 2007 525i erratic idle I scanned the vehicle came up with code 1415 replaced the MAS New from BMW it didn’t work service engine light went light came on I put my old Sensor in no light on just erratic idle  need help please. Just frustrated I did have the starter replaced about 2 months ago I was at work and I couldn’t do it myself I think the problem may be there but repair facility refuses to look into it for something they might have been missed thank you 

Morning Ronald

Welcome to the Forum

First it would be unlikely the a Starter would cause this fault code as the starter is underneath and the issue you have is at the top. A fault code indicates a problem it isn't  necessarily the cause, start by looking for leaks in any of the Vacuum lines and hoses on the Inlet side after 13 years the hoses on your car will quite probably be dry and cracked in places. Also check all wiring and plugs if cleaning use a good electrical contact cleaner.

The replacement you brought,  is it correct for your model ?

As an after thought check the engine mounts I am not sure whether your mounts have a vacuum link

Dave

 

My thought is that the maf sensor is working correctly. 
did you reset the adjustments and parameters after replacing it? 
I agree with @Greydog. 
check the inlet pipe between the maf sensor and the throttle body for any cracks, especially on the elbow part.  Throttle body could also be the issue. 
my x5 has the 3.0i engine and was all over the place with idle and cutting out etc. 

it was the throttle body which was faulty , but while I replaced it, I found the inlet pipe had little splits in it at the elbow folds and was leaking in air, confusing the mixture as the new maf sensor was saying one thing and the air ratio was another. The old maf sensor was reading a lower value and the engine had over compensated for it. 
Check for splits, reset the values and see where it goes. 
 

when I put the new sensor in I only cleared the codes with my scanner did I have to disconnect the battery for 15 to 30 minutes so the computer would adjust to the new sensor I don’t know about any adjustments thank you for getting back to me 

Good morning thank you for reaching back to me I don’t know how to reset the perimeters and adjustments unless it is only to Disconnect the battery for 15 to 30 minutes is that something that I need to do thank you please let me know 🙏

Hi Ronald. What scanner are you using? 
I have a cheap 110 obd unit, an autel eu705 (or something ) and a pc with bmw 1.4.0 programme on it. 
 

all give me an option to reset adaptations in the dme menu. 
 

I have an old scanner hand held I had a body shop that I deliver paint to they ordered me a BMW MASS AIRFLOW SENSOR I replaced it on Saturday morning I did not disconnect the battery the car idled good so on Sunday morning I went for Gas and the car started to idle erratic and the service light came on  so I put the old Sensor back and cleared the codes 1415 the car runs fine just erratic idle when stopped at a light Any Ideas thank you very much for getting back to me I appreciate it anything you can think of that I did wrong 😑 

Borrowed from another site… 

unplug the maf and clear the codes… see what happens.

i think me and greydog are on the right lines

Could also be a stuck idle control valve. Remove it and give it a shake… it should click clack noise opening freely.