B2300 SE Regular Cab 2WD L4-2.3L VIN A (1997)
Vehicle Speed Sensor: Description and Operation
VEHICLE SPEED SENSOR (VSS)
Detects vehicle speed. Outputs frequency signal to PCM. PCM controls operation as follows:
1. Fuel injection
2. Ignition timing
3. Shift/torque converter clutch scheduling
4. EPC
Operation
Uses a variable reluctance sensor. Sensor generates a sine wave type waveform with a frequency.
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High frequency as vehicle velocity increases.
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Low frequency as vehicle velocity decreases.
NOTE:
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Installed in transmission (4x2) or transfer case (4x4).
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If EPC solenoid is shorted to ground, PCM outputs DTC for VSS. Diagnose EPC solenoid first, then check VSS.
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If the vehicle speed sensor or circuit has an open or short, Diagnostic Trouble Code No. P0500, P0503, Pl500 or P1501 is output.
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If the vehicle speed sensor circuit fails, no 3-4 or 4-3 shifts or torque converter lockup will occur.
