If you have a multimeter remove and test the fuses for continuity (OHMS) as fuses can look OK but they have blown. If your replacing fuses ONLY replace the with one of the Same colour and Amp rating.
Question edited for clarity. changed your Poly Vinyl Chloride (PVC) into Positive Crankcase Ventilation (PCV), and added some punctuation to make real sentences.
Your car is run by computers, the computers have diagnostics and will tell you what's wrong. You can't guess faults like you have. A Professional Grade Scan Tool computer can diagnose all the computers, modules, sensors and systems in about 40 minutes. It can even record what happens and what goes wrong as you are driving!
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To turn off HDC on a BMW, all you have to do is press the HDC button located on the center console. The button will have an image of a vehicle going downhill with a speedometer above it, and you'll know it's off if there are no lights illuminated above it. If you ever want to turn the system on again, just press the button again.
Since you fixed the fault by scan advice and was ok and on testdrive another limp mode came up, just check again with your scan to see what is the possible cause for it. Probably the crank sensor.
Check the basics first. Is battery fully charged? This is the most common reason for a no crank, no start. What exactly does it do when you turn the key? Nothing at all, no lights, no 'click' as you turn the key. A slow lazy crank?