Faulty Engine Speed Sensor
Engine Speed Sensor harness is open or shorted
Engine Speed Sensor circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
Engine RPM Signal TD Short To Ground is the generic description for the P1398 Audi code, but the manufacturer may have a different description for your model and year vehicle. Currently, we have no further information
about the P1398 Audi OBDII code.