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 P2159 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
Detecting Condition
Possible Cause
DTC
Strategy
case1
Plausibility Check
Open or short in harness
Poor connection or damaged harness
VSS
case2
Electrical Check
Enable
Conditions
Engine speed >2100rpm
Engine Load > 446 mg/rev
No fuel injection shut off
Coolant Temp. > 60?(140?)
10V < Battery voltage < 16 V
Vehicle speed > 0
Threshold Value
Vehicle Speed = 0 with high engine speed and engine load
Signal voltage exceeds threshold
Diagnostic Time
60sec.
10sec.
Mil On Condition
2 Driving Cycles