So, I replaced my head unit with an Alpine, all is fine there. But...my mechanic who has PIWIS can only code one key at a time, not multiple. The keys are not the issue as he's coded each one but then it locks out the other key. He thinks but isn't sure it might be an issue with having an aftermarket head unit. Is there something in the PCM unit/OEM head unit that has anything to do with key coding? I'm hoping he's incorrect and just can't figure it out. I'd like to save a trip to the dealer but I also think I need to have more than one key...