I used to get the green wrench light occasionally and recently the "pull over and stop" light came on in my 2008 Escape Hybrid a minute after starting it. The engine would not stay on for more than a few seconds. I thought it might have something to do with the 4 kWh Enginer PHEV system I had installed. But it turned out it was just corrosion on the 12 volt battery connectors. I disconnected the 12 V battery, scraped and cleaned the contacts and sprayed them with DeOx. Problem solved. Neither the green wrench light or the "pull over and stop" warning come on anymore. I think a lot of these issues may just be due to bad contacts.