Just ran into the same problem myself this morning. Last night I had my first encounter with the RCM. Had me stranded at work at 3am. Of course I hit this web site immediately on my phone and was able to get the car to start. Drove home with no issues. This morning I decided to swap my keychain case with one I ordered on eBay (before checking to see if my car would start today). Then went outside and tried to start it with new fob case and did the famous 2x start and stop thing. Thought it was still an RCM issue from last night and removed the RCM and did the solder repair. Reinstalled and same thing over and over. Didn't even register to me to think of the transponder chip. I never swapped it over! Duhhh! Feel like an idiot. I drove my other car to work today so I will swap over the chip in the morning. Should be what is causing the issue.
One thing I have a question about is the locks do not actuate at all when car is not running. Both on the switches at the console and key fob. Key fob will not actuate them in either state (running or not) even with original case before the swap. Any clues as to the cause of this? Thanks in advance.