Yes, the valet key has the EWS chip to handle the "coded start."

I can't yet see the figures in Qsilver7's post, but ...

The photo in post #1 of my thread referred to earlier shows the setup:
https://xoutpost.com/bmw-sav-forums/...r-options.html

And I also have one intact original diamond key that came with the car. With the 3 pairs of valet+fob, I have 4x fully functional things to do the keyless entry and start the car. It is said there is a limit of 10x EWS chips per car. I don't know if there is a limit to the number of remotes that can be programmed.

I have not cut a valet key open, but it appears to me to be solid state. No panels or batteries or anything that I can see. It looks like that gray plastic head is cast over the head, enclosing the circuit. From a basic understanding of how things like that work (that may be wrong, and if I could see Qsilver7's figures, I may know more), underneath that gray plastic is some sort of coil (performing the function of a coil and antenna, even if it does not look like one) that can receive the 315 MHz magnetic field, converting it into an electric potential to drive the circuit with an EWS chip. The EWS chip wakes up, reads the coded signal on that 315 MHz carrier signal, and responds with its own processed output code, sending it back on (possibly) the same coil (now used as an antenna).

So basically it's a circuit underneath the gray plastic.

• There is no battery.
• It contains the EWS chip coded to the car's security system, that you can "only get" from BMW.
• One step up from the valet key is a "master key" (not the diamond key; this has no remote functionality) which does everything the valet key does, also unlocks the glove box, and has a light built in. That needs a battery to power the light. I don't have one, just read about it.
• Neither the valet nor master key does anything regarding keyless entry. Just the mechanical lock and the EWS chip + communications.

The cut-off diamond key fob shown in my pic does all the keyless entry stuff, and can be (must be) programmed to work on a new car or when things need to be reinitialized. They are optional. You can use the valet key to mechanically unlock the driver's door, turn the ignition, and communicate with the EWS to start the car. Those fobs also have their own EWS chips, power source, antenna, etc.

So when I'm using a valet key + fob, and scanning for codes with my Foxwell (or previously PASoft BMW Scanner 1.4.0), I would get a low priority EWS warning since it finds TWO EWS chips - a valid one in the valet key, and an invalid one from the fob which matches whatever car it came from. But it does not cause any problems.

If you were to buy a new diamond key from a dealer, based on you providing your VIN, they'd sell you a key containing a BMW-programmed EWS chip (one of 10 for your car). It would rely on you still having the original car-side part of that system to communicate with. The keyless entry functionality would need to be programmed by going through the standard procedure in your car.

I expect one day my computer will show me Qsilver7's figures and I may need to update this. But as far as functionality goes, there are no problems.

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2001 X5 3.0i, 203k miles, AT, owned since 2014