Learning to read wiring diagrams is always a good thing! :)

MAF testing can easily be done by while the engine is running and the MAF disconnected from the airbox, tap hard the outside of the sensor with the handle of a screwdriver (not ass beating hard). If you get a stumble in the idle then the film sensor is loose. I have had issues with MAFs a lot lately and even OEM which I believe has been infiltrated with fakes into the supply chain.

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Just wanted to check...

Do you have a good scanner like Foxwell or ista-d, etc?

Are all your o2 sensors working and showing no codes?

Are you getting a low signal code from the MAF?

And not sure what if any bearing it has on it, but do you happen to have any license plate lights and rear fog light out?(specifically the left side) This last one is probably just a coincidence but I was getting bad MAFs that started when I had those lights out and I had a ground issue causing that and since the MAF has a 2nd sensor reading the ground it would NOT surprise me that a ground somewhere else (hot to ground) could screw up the sensitivity of a ground in the MAF.

But I had the same [emoji90] for a while that caused me to want to hunt down the BMW electronic system engineer and fixing the lights saved my MAF ir like I said complete coincidence...[emoji28]

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If you have a 3.0 engine the OE maf was made by Siemens not Bosch.

There's a bunch of letters on the diagrams, such as
HZHL, NTCHL, NTC, HEIZ etc. Is there a list somewhere that explains what they all mean?

I see these everywhere.
Not sure if the bar is a fuse?
https://i.ibb.co/VMDjrTH/Screenshot-...115-Chrome.jpg

The bar could be anything. The transistor and bar symbol mean there are some electronics and give rough idea of what's going on.

Signal types. Most of them are found in WDS Component and signal information -> Signals.

A resistor and transistor connected to module (board) internal ground. A rough representation of a load and signal transfer.

I see what you are talking about. In this example it is the rear seat heating. I think it has to do with the feature and the specific wire. In this one example, it looks like "LEFT" and "RIGHT" being part of the abbreviation. I understand the wire cross-sectional area as the middle number, and the color of the insulation as the bottom.

I tried searching the abbreviations section on TIS and could not come up with ANYTHING. But I do believe its an acronym for something. Is it perhaps the terminal name?