ECM unit

[Andrew Shadow]

If it is a used ECM, from what I understand you can not register a key to it if you do not have an existing HISS key that is already registered to that ECM.
If it is a new ECM that has never had a key registered to it, again from what I understand, you will also need new keys that have never been registered to an ECM before.

When new keys are registered with an new ECM for the first time, a code is created in the ECM. A matching code is also created in the chip that is in the new key. From that point forward that key chip will only work with that ECM.

You can buy new keys and remove the chips from them. You can then replace the chips in your old keys with the chips harvested from the new keys. You will then need to register these new chips to the new ECM. This allows you to keep your old keys that match your existing lock cylinders.

I may be completely wrong in my understanding of how this system works as I do not have it on my ST1300, so seek confirmation. My best recommendation is to wait for John (@jfheath) to chime in to confirm or correct what I have written as he is more knowledgeable of this system.

John also has previously provided a link to detailed explanation of the Honda HISS system and how it works.
Have a look through it while you wait for John to wade in here. It might have the answers to your questions.

The link to that article is below;
Honda Ignition Security System.

 

[Chris09]

FWIW and not sure if it's maybe a DOT thing but I've got a '12 Wrangler and I was told that, as long as you still have two keys, you can cut then program a a third key but if you get down to only one, you're locked out and need to take it to the dealership.

 

[Chris09]

oh, well that's good to keep in mind. You gotta have a couple of keys that work for that particular ECU. Even mine? Mine look like my old '92 Accord keys; doesn't look like anything in there.

 

[jfheath]

@Andrew Shadow is absolutely correct. With a new ECU for an HISS bike - you need brand new keys. All of them need to be new.

The reason is that once a key has been regsitered with one ECU, it cannot then be re-registered with another.

However, you can re-register your own keys with the same ECU. eg I have 4 keys registered. I lost one once so I re-registered the remaining 3. Then I found it again and re-registered all 4. You cannot re-register just one. If you do, the other will not work. You have to re-register all of them.

(If you read my previous post - it was wrong. I've deleted it.)

 

[Andrew Shadow]

Even mine? Mine look like my old '92 Accord keys; doesn't look like anything in there.

Assuming that your ST1300 is one that was originally sold by Honda in the North American market, it does not have the HISS system and therefore does not have the chip in the key.
HISS equipped ST1300's were never sold in the North American market by Honda.

Unless you can find a good car thief who has figured out how to disable/bypass the HISS system, the answer below is from post # 21 above;

If it is a used ECM, you can not register a key to it if you do not have an existing HISS key that is already registered to that ECM.
If it is a new ECM that has never had a key registered to it, you will also need new keys that have never been registered to an ECM before.