i have accord 2000 LX where i had battery replaced and transmission computer replaced recently. today when i was starting the car with regular spare key , it doesn't start. when i use my regular key which i was using(which was used by mechanic also ) it starts. what might be the issue here

 

I think in 2000 there isn't a separate tranny controller. It's all together in the 'powertrain' controller. Including the immobilizer??

So when the mechanic did that, he needed ALL the keys to enable them for the immobilizer. I believe you can't add/subtract keys without deleting the old list entirely. So maybe your valet key doesn't work anymore either.

 

You are probly gonna have to take all your keys in to get them re-programmed to the computer. If you mechanic doesn't have the software then you are gonna have to have a dealer do it .

 

the mechanic did it wrong, up to i believe 6 keys can be programmed for one vehicle, he must not have programmed the other ones correctly. you're probably going to have to take it to the dealer.

 

when i comes to keys Go to dealer, it's always best.

 

If your spare key doesnt look like your original key, chances are you don't have a programmable spare key. Be sure to get your spare from Honda or at least make sure it's T5 blank from Ilco.