po502 speed sensor we change but not work good could be another failure

Question

My chevy van enter the code po502 speed sensor automotive and you change the sensor but the fault was that the speedometer does not work so well or van to go running could be otherwise the case is not under

Answer 1

P0502 Vehicle speed sensor circuit low input

The solution is not with the speeds sensor but the PCM (power control module) you will need to measure voltage with the harness to the VSS disconnected and key on engine off. measure voltage A and B together the voltage should be 4.0 to 5.0 volts if not within this specification a PCM replacement is required.