code po717

P0717 pertains to transmission input speed sensor no signal. Early years of the 4T80 had issues with the input speed sensor, but that is not necessarily saying it is a sensor fault. Ideally, if you were(or are) able to read ISS data, and determine there is no signal, then you could validate the condition. Other possibilities include the PCM, the wiring for ISS circuits, the internal trans harness, and the sensor itself.