I've been having trouble with my 05 crossfire starting. I had the mystery no start a couple years ago and had the RCM soddered. Yesterday, when I went to open the car the remote wouldn't work, when I opened the door the alarm goes off, and it wouldn't start. I read the forum and disconnected the battery for a few minutes and it worked like a charm. Today, I went to get in it and the remote opened the doors but it wouldn't start. I disconnected the battery and still nothing. After repeating this process 3 times it finally worked, about 6 start attempts. I took it to have it diagnosed:
15 Pulse Module
1 SKREEM
1 PCM
The battery and grounding cable checked out fine.
I can't seem to find any information on the pulse module. I really don't want to take it to a dealer before I know more.
I appreciate any help.

 

Stay the hell away from dealers. Take it to a local shop known for their work with Mercedes products.

Sounds like a bad battery or skreem to me.