The Vehicle Speed Sensor (VSS) generates a waveform with a frequency according to the speed of the vehicle. The signal generated by the VSS informs the ECM not only if the vehicle speed is low or high but also is stopped the vehicle or not. The ECM uses this signal to control the fuel injection, ignition timing, transmission/transaxle shift scheduling and torque converter clutch scheduling.
The ECM sets DTC P0501 if there is no vehicle speed signal from wheel speed sensor while both engine speed and mass air flow are higher than predetermined threshold during predetermined time.
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal check (implausible)
Poor connection
Open or Short in power circuit
Open or Short in signal circuit
Open in ground circuit
Faulty VSS
Enable Conditions
IG ON
Battery voltage 10~16V
Engine speed < 3600 rpm
Coolant water temperature > 70?
Intake air temperature -10~80?
atmospheric pressure > 75kPa
Threshold Value
Vehicle speed signal during fuel cut-off = 0 km/h
Diagnostic Time
4sec
MIL ON Condition
NO MIL
Frequency of VSS is relatively increasing to the vehicle speed. In case of low speed, the sensor outputs low frequency's signal. And, It outputs higher signal by the speed increasing.