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MAF or ECU

2K views 6 replies 7 participants last post by  saltshaker185 
#1 ·
Hey Guys,
I've been in an ongoing battle to get my car to pass inspection. Now there've been a lot of theories from people on this and other forums but after speaking to a mechanic who seemed to know his shit and not just bullshit me, it sounds like it's either the MAF or the ECU. Unfortunately, these aren't parts that you should just replace to "check and see" if the car performs better. So, I was wondering if anyone has ever tested their MAF to see if it's working properly. There's a procedure in the Bently manual on how to do this, but i haven't read it in a while and it seemed pretty vague. Anyone have any experience with this?
Also, if it isn't the MAF, does anyone know how to check the ECU or how to replace it? I'm not sure what BMW calls it in order to look for it. Perhaps DMU? Thanks a lot guys. It's good to be back in my Bimmer after this long winter.
-Nookatee
 
#4 ·
I dont see how your ECU could go bad other than being friend, but then your car wont start.

If your mechanic says it's the MAF, there are procedures i've heard about by testing the voltage of the MAF or some such nonsense. It should be in the bentley manual if you have that.
 
#5 ·
Well... if that temp sensor inside the MAF meter is not sending or recieving the charge... OR if the wire heater is faulty within the MAF meter then it needs to be replaced.

If your heating element inside the MAF goes bad your ECU will go to a "limp home" mode... which could be your problem... the car can be driven... but it will have deduced power and performance.

There are procedures for testing the imputs and outputs of the MAF... as for the ECU... that is a direct electrical component... and unless it is partial operational... meaning that is has some how jumped to "limp home" mode by some reason... then that would not break. It is electrical.

Get your ECU or car hooked up to a BMW machine... they will tell you whats wrong in about 2 mins.

Good luck,

Les
 
#6 ·
not sure whats really going on.. what are you testing for? whats the problem thats not allowing it to pass inspection?

as said above using a modec or a GT1 from the dealership will be able to pinpoint pretty much any working fault.


do you have anyone in your area that can swap out the MAF to just test? if your mechanic is a BMW mechanic im sure he must have another car around the garage to swap and check.
 
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