How to Diagnose Car Transmissions

It is very important to follow the proper protocol for checking electrical issues in a transmission. A proper diagnosis should start with the battery, this is true. A bad ground can have all kinds of effects on electrical circuits. The components at fault should be checked with a multimeter or a proper scan tool if applicable. I do not think many entry level technicians have expensive scanner so doing a test with a multimeter is very important in my opinion because not everyone has the specifications for all the vehicles. In conclusion testing the fault codes that are present, checking the circuit, the wires, connectors, and the components are rudimentary if the luxury of service information is not readily available. It should be done before changing any components.