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
DTC Strategy
? Rationality 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
Threshold value
case1
? No vehicle speed signal (during injection) < 3.8 kph
case2
? No vehicle speed signal (during fuel cut-off) < 5 kph
Enable Conditions
? Engine speed > 3000 rpm
? Engine load > 50 %
? Coolant temperature > -7.5?
? Engine speed : 1520-3520 rpm
? Fuel cut-off : True
Diagnostic Time
? 2 sec
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.