2010 CR-V RE4 keys?
How does the car know its got the wrong key?

I lost one key, and then found it.
Not before the dealer had come and picked up the car, reprogrammed it for a new key.

The lost key still unlocks the car physically, but will not start.
Can I turn it into a dumb key only by removing the guts?
Without any button pushing, does the car talk to keys in normal operation too?

Thanks!

 

When they programmed the new key they did a lost key reset that wiped all the keys out. They then program in the newly cut key and any old keys you may have had with you at the time of programming.

The previously lost key will need to be added to the programming at the dealership. A "dumb" key will not start the vehicle. There is an immobilizer system reading the key as you crank the vehicle.

 

Thanks!
I figured this was the case...

Just as an aside, any idea how the car talks to the smart key - RF or contacts in the key?

We have a non smart key too (no remote function) so assume it too has to talk to the car?

The keys appear to be cut physically the same...