It's probably to late to answer this question, but what the hell. $450 is a really high estimate to fix this, I could put a new lock in an program it for less than half of that!
I run into this problem all the time, 99% of the time it's just the connecter in the back of the ignition lock not making good conact. Take it to a locksmith and have them check the connector, it can probably be repaired without replacing any parts. It takes less than 2 minutes to remove that lock and check it.
And NO, there is no tranponder on these systems.