Dodge ECM codes are special ciphers found inside the car's computer that help troubleshoot a problem from a damaged or malfunctioning sensor. Automotive technicians use the codes saved on an ECM and cross-reference them with a chart to see which components are sending the incorrect signal to the computer.
The ECM codes are used for engine diagnostics. They can be read using a special machine called a code reader, which plugs into the on-board computer by means of a diagnostic plug. When the car is turned on, the machine will be able to detect any codes saved on the Dodge vehicles ECM.