P0601 code help

I have a 01 GC Sport with a 3.3. Has aprox 144k on it. I recently stumbled upon the engine light being on. Of course it's time for inspection emissions test. So I took my scan tool and read the code. It comes up as P0601. I reset the code and drove 106 miles. The light stayed off until I turned the key off and re-started the engine. As soon as I turned the key the light came back on with the same code. I popped the harness plugs off the PCM and used compressed air and re-connected. That did not change anything. Now I'm wondering if the code appears as I turn the key if its possible the problem is within the ignition switch? Anyone have any ideas? And how might I be able to check this theory? Any suggestions or assistance would be greatly appreciated!
Thanks in advance!

P0601 Dodge = Internal Control Module Memory Check Sum Error
The PCM is telling you it needs to be replaced.

Thanks for the info. After doing some Internet searching I've seen some older posts about people changing out the PCM without that fixing the problem. Someone had mentioned a bad wire in the harness going to the PCM and another had mentioned about the ignition switch. But those posts are so old it wouldn't let me respond to them. I also saw where people have had the PCM flashed at the dealer some times it fixed it and other times it didn't. I just don't want to spend a ton of $ changing parts and troubleshooting.
Thanks again for the response.

Yup, 99% of the time the PCM is the fix. It's that nagging 1% that makes everyone hesitate. The only other fix I've read of in years of cruising forums and reading articles is a wiring issue. Unfortunately specifics were lacking. The sad fact is many have stated they can drive around with this code for years without having any other issues but those living in states with required emissions testing, like you, are screwed. PCMs can be had for $150 to $300 at internet sources. They come preprogramed and ready to install, many with a lifetime warranty. Parts stores sell them for around $300.

http://www.obd-codes.com/p0601