Neon L4-2.0L SOHC (1995)
Vehicle Speed Sensor: Description and Operation
No Vehicle Speed Sensor Signal
NAME OF CODE:
No Vehicle Speed Sensor Signal
WHEN MONITORED:
With engine running more than 31 seconds, engine temperature greater than 180°F.
SET CONDITION:
No signal from the vehicle speed sensor (TCM) is present for more than 11 seconds.
THEORY OF OPERATION:
The vehicle speed sensor is a hall effect type sensor used to detect the transmission output shaft speed.
The PCM calculates the vehicle speed based on the VSS signal.
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The PCM supplies 8 volts from cavity 44 to power up the sensor.
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Sensor ground is supplied by PCM cavity 51.
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The PCM also supplies a 5.0 volt pull up voltage to the sensor from cavity 5.
The VSS signal is created when the sensor alternates the 5.0 volt pull up from high to low.
POSSIBLE CAUSES:
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Open or shorted signal circuit
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Speedometer pinion damaged
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Open 8 volt supply circuit
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Open sensor circuit ground
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Failed speed sensor
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PCM failure
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Connector Terminals/Wires