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 PCM not only if the vehicle speed is low or high but also if the vehicle is or is not moving. The PCM 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.
The PCM evaluates engine speed and mass air flow if there is no vehicle speed signal. This evaluation of both values will detect open circuit or short circuit errors on the wheel speed sensor. The PCM 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 the predetermined time.
ITEM | DETECING CONDITION | POSSIBLE CAUSE | |
Case1) | DTC Strategy | ● Plausibility check | ● Open or short in harness ● Contact resistance in connectors ● Faulty wheel speed sensor |
Enable Conditions | ● Engine speed ＞2100 rpm ● Engine load ＞250 mg/rev. ● Coolant temperature ＞ 60℃(140℉) ● 10V< Battery voltage ＜16V ● No fuel shut-off | ||
Threshold Value | ● Vehicle speed=0 with high engine speed and engine load | ||
Diagnostic Time | ● 60 seconds | ||
Case2) | DTC Strategy | ● Electrical check | |
Enable Conditions | ● Vehicle speed ＞ 0 ● 10V＜ Battery voltage ＜16V | ||
Threshold Value | ● PCM detects abnormal input voltage of the signal circuit | ||
Diagnostic Time | ● 10 seconds |
