To check the sensors, you will need a shop that has a factory level scan tool like a GT1 or Autologic, and can scan the system for faults.

For example, on the Autologic, a very helpful screen you want to look at is called:

Deviation, Ridel Level, From Specified Value

So first you scan for codes to find out where to start your diagnosis. Let's say the Autologic tells you to check the RF ride height level sensor. You can then swap the two front sensors to see if it's a bad sensor or if it's a wiring/module issue. If the code stays on the same wheel's sensor, immediately suspect the module. If the problem moves with the sensor, you have a bad sensor. To confirm that it's a bad module and not the wiring, (usually it IS the module or sensor), you can swap the signal wires of those sensors, and again scan the car with the Autologic. The above mentioned screen will show you where the problem is.

My first question to a new Indy shop you are considering would be: Do you have an Autologic or GT1? There are a lot of versions of the GT1 floating around, some very inexpensive, and I can't speak for the competency of all those versions. But the Autologic is a very serious investment for a shop, and makes most BMW electronic troubleshooting very straightforward; quite an awesome scan tool. And NO $9,000 Snap-on, (or MAC or Matco or OTC) scan tool can do ANY of this stuff. So if a shop you are considering tells you they use a Snap-on Verus, Modis, Ethos, Vantage or Solus, (as many shops try to do,)...your answer should be: "Not on MY BMW."

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2014 BMW 328i Xdrive
2011 BMW 335i M-Sport
2008 BMW X5 4.8i Sport
2000 BMW 528i 5sp