Code P1509 on Honda Civic 97?

Honda Civic 97 4 cylinder 1.6L engine, Automatic transmission. I was cleaning my fuel injectors and forgot to plug in the IACV connector. I turned on the car and the check engine light came on. I turned it off, reconnected the plug, turned it back on but the check engine light remains. How can I clear the code?
My car does have an idle issue where it will push 2rpms at idle and settle down to 1rpm or lower, however, it never lit up the check engine light until now when i forgot to reconnect it.

I understand that most auto parts places like autozone will clear your codes for nothing, or at least a small fee.

A local parts store can usually clear the code or it will clear itself after a number of driving cycles if the issue is resolved by plugging the IACV back in. The high idle speed be normal fast idle on a cold start or it may indicate that the throttle body/linkage or IACV need cleaning or a vacuum leak or the IACV may be defective. Try cleaning those items and check for vacuum leaks… Test IACV.

Go to an auto parts store and they can read and clear the codes. It's a free service.
Anyone who states 1 and 2 rpms instead of 1000 and 2000 rpms shouldn't be playing mechanic on their vehicle!
All motors made by Honda have a common issue with the valves getting tight and they need adjusting every 60,000 miles. Start with having the valves adjusted.

If you unplug your battery and wait a while, the check engine light should stay off and not return.

P1509 is RACV Circuit Malfunction (rotary air control, same as idle air control). It is telling you the connector is still not making contact or there's a wiring problem.