I got a spare oem AP2 and want to use it as a back up part. My understanding is that my current keys will need to be programmed to it. Is this something we can do ourselves or will need help from a locksmith/Honda dealership?

 

What model year is your car and the "spare" ECU? I can't access your Public Profile -- got one?

I don't think the ignition key has anything to do with the ECU other than allowing the immobilizer to turn it on and pre-2006 ECUs are not programmable anyway.

-- Chuck

 

My car is 2005 and this Ecu came from 2004 s2000

 

Most honda Ecus from early 00s onwards including Ap1/ap2 ecus can be reprogrammed for new/existing keys to interface with the immbilizer. The Autel ap200 100$ dongle can do this at home.

 

Dam wish I knew the Autel AP200 could do it.
I just paid the dealer $100 to reprogram a 2nd ECU to accept my keys.