Steps you need to follow to program a few more transponder keys along with the primary key is as follows:
To reprogram additional keys, you'll have to be quick and precise with the timings, and you will hardly get five seconds to make it work.
As soon as you turn on your ignition again, immediately turn it off within a fraction of seconds.
Please do the same with the operational transponder key by turning it on and off.
Now observe the new transponder key that you have been working on programming, start the ignition using the new key, and make sure that the security lights turn on, but this time for a few seconds.
Without wasting any time, do the same process to program transponder keys. Don't forget that you have very little time to complete the process. The light turning ON indicates that you have successfully programmed all the keys.
You can program around three transponder keys at a single time.