Is it possible to "unprogram" the ECU so that the immobilizer will not recognize one of the keys?

Or will I need to replace the entire key assembly to prevent my car from recognizing one of the keys? If so, how much would it cost to replace the entire set? (i.e. ignition, door, trunk, glove box)

I remember someone mentioned this a while ago (because his house got broken into or something), but I couldn't find the thread using the search.

Thanks

 

You could probably do it by changing ECU's then replacing your existing keys with new ones cut to fit your current locks BUT, programmed to match the ECU immobilizer.

 

Helm says:

"If it is necessary to rewrite the ECM, the dealer needs the customer's vehicle, all its master keys and valet keys, and the Honda PGM Tester equipped with an immobilizer program card with the latest version of PGM Tester software. Any key that is not learned during rewriting will no longer start the engine, except keys duplicated with the Ilco Code Key Duplicator."

This says to me that the dealer can rewrite the ECM to recognize only the keys that you want it to.

 

Awesome, thanks ...

But ya, finally able to get a hold of my service advisor, and he told me to bring the keys in and reprogram everything

 

I don't think you need to replace the ECU because of a lost key. The ECU remembers something like 4 keys. The OEM key's themselves are not programmed. The OEM keys have a permanent unique ID, like a serial number imbedded on the transponder/chip inside them. The ECU is simply programmed to handshake/accept up to like 4 of these unique transponder ID's. If one is lost or stolen, you need to add another (new) key's unique ID in order to "bump" the lost key's unique ID from the ECU's memory. I think the dealer will still have to do this for you. Like someone else above said, take all your key's with you when you do it. Re-add all the key's you still have plus a new one to replace the lost one.

I think this is true, you could have only one or two keys programmed into the ECU. However it would allow other keys to be added later without any way of testing. If you fill all the ECU's memory for keys if someone adds one (or you suspect someone has) you would be able to check because one of the existing keys will cease to work.