What do I need to do to replace the ecm?

The replacement ECM must be programmed in the vehicle, you can get a preprogrammed unit by searching Google or Ebay. Remove the ECM plastic dirt shield ,loosen the screws that hold the wiring connectors to the ECM, remove the connectors, connect and install the new ECM, program the ECM. Here is the replacement instructions and location of the ECM. Check out the images (Below). Please let us know if you need anything else to get the problem fixed.