The Wheel Speed Sensor (WSS) generates a waveform with a frequency according 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 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. Also the WSS signal is used to detect rough road driving condition.
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. Also the VSS signal is used to detect rough road driving condition.
Item
Detecting Condition
Possible cause
Monitoring Strategy
? Signal check
? Open in signal circuit
? Open in battery and ground circuit
? Short to ground in signal circuit
? Short to battery in signal circuit
? Faulty VSS
? Faulty ECM
Case1
Threshold value
? No vehicle speed signal(during injection) : < 3.75kph
Enable Conditions
? Engine speed : > 3000rpm
? Engine load : > 50%
? Coolent temperature : > 65?(149?)
Diagnostic Time
? 20 sec
Case2
? No vehicle speed signal(during injection) : < 10kph
? Engine speed : 1520 ~ 4000rpm
Fail Safe
? None
This is the waveform of vehicle sensor when it drives 40Km/h.
The voltage at point ? should be below 0.8V and at poiont ? should be above 7V.
The frequency of vehicle sensor must increase as the RPM increases.