The Wheel Speed Sensor (WSS) generates a waveform with a frequency proportional to the speed of the vehicle. The signal generated by the WSS informs the ECM not only if the vehicle speed is low or high but also if the vehicle is or is not moving. The ECM uses this signal to control the fuel injection, ignition timing, transaxle shift scheduling and torque converter clutch scheduling. The WSS signal is also used to detect rough road conditions.
If the vehicle speed signal is below the specified minimum value under driving, ECM sets P0501.
Item | Detecting Condition | Possible cause |
DTC Strategy |
•
Plausibility check |
•
Poor connection
•
Short in harness
•
ESC(ESP) control unit
•
ECM |
Enable Conditions |
•
Fuel Cut On
•
ECT > 40C
•
1000 < rpm < 4500 | |
Threshold value |
•
Vehicle speed raw signal < 2.5mph | |
Diagnosis Time |
•
3sec | |
MIL On Condition |
•
2 Driving Cycles |
Fig. 1) Normal waveforms of VSS (from ESC(ESP) ECU-5KM/H)
