TO be honest i don't know, maybe it's cutting power to things related to the transaxle, i have a 6 speed so i cant tell you.

But i can tell you that when my RCM went out my engine randomly died, or wouldn't crank. The speedo would go all the way to 160 and back. I think taking 15 minuets of your time to check it would be worth the hundreds of dollars your going to spend taking it in to a shop.