I recently lost the only known key to a 2002 Accord I received in a car swap. He said there was only one key when he purchased it a few years ago. I was just going to buy a new lock cylinder and replace it. The procedure looks simple enough in the Haynes manual; they make offhand reference to the immobilizer, saying only that if the immobilizer is replaced the car needs to be reprogramed at the dealership. What I am thinking is, though, that if I just buy a lock cylinder online (found one for $93), if the key is chipped, (are 2002 Honda keys chipped? This one doesn't look like the obviously chipped one my friend has for his 2003 Civic), the new key isn't going to match without reprograming. Been looking for days, and the car is in a shared space, and needs to be moved ASAP. How much trouble will this be if I can't find the key; can really only look one more day before I must take other action. Please help!!

 

Call a local locksmith; he/she can cut a new key for you and get it programmed.

 

Or, take the registration to your local honda dealer and have them make a new key (about 70 to a 100 bucks... chipped key). The dealer WILL want to see both the new key and the car before they'll re-program the imobilizer. Had to do that with the wife's 2000 Accord (wanted a 2nd key made so I could move the car). It cost 70 bucks at the Honda dealer, but the key (new 1), and her's still work like they were designed to. Sent my wife to my local dealer with the registration slip, and they made me a new key for my 97 Accord. Went back there later the same day and had them cut a 2nd key (the code was still in the computer) as they both worked great. Cost 5.20 for a pair of genuine Honda keys (without an imobilizer circuit/not chipped).
I know people are scared/afraid to get gouged at the dealer, but Honda parts are reasonably priced compared to other models. BTDT. Just my take on it... YMMV.
Or pull the trunk lock out and take it to a locksmith, and have him cut a key. You'll still need to visit the dealer so he can program the ECU so it'll run. The problem is your car is too new.

 

Dealer or local locksmith - call around as some might not be able to program the new key(s).

Me. My new to me 07 Accord only came with one key. Ordered two "blank" key fobs (with buttons) for ~$40. Took car, one working key and the two "blanks" to local locksmith. They cut the two and programmed them for ~$50. Now have three working keys for it .

Hint, there is also an "e-brake" override for the immobilizer the dealer can give you....so a cut un-programmed key and the code will start the car. This allows you to drive the car to a place that can then program the key to the PCM/ECU.