For a used ecm you can rewrite the vin just with you maxisys no need to buy subscription , just go under special function and choose ecm replacement you will need the pin code from the dealer . It will be an easy walk through with the scanner just follow the steps

 You should be able to call the Dodge dealer with the VIN number and tell them that you need the SKIM #.

 pin codes in person only with prove of ownerships in most cases.