Neon L4-2.0L DOHC (1996)
Vehicle Speed Sensor: Description and Operation
No Vehicle Speed Sensor Signal Trouble Code
With Electronic Automatic Transaxle
NAME OF CODE:
No Vehicle Speed Sensor Signal
WHEN MONITORED:
With engine running more than 31 seconds, engine temperature greater than 120°F, transmission not in park or neutral, brakes not applied, engine
RPM greater than 1800, and MAP vacuum less than 11".
SET CONDITION:
No signal from the vehicle speed sensor (VSS) for more than 11 seconds.
THEORY OF OPERATION:
The vehicle speed sensor signal is provided to the PCM by the TCM. The signal is calculated by the TCM based on the output speed sensor signal
and the speedometer pinion factor. The PCM supplies a 5 volt pull up voltage from cavity 66 to TCM cavity 58. The sensor signal is created by
the TCM alternating the signal from 5V to 0.3V.
POSSIBLE CAUSES:
-
Open or shorted signal circuit
-
Speedometer pinion factor not programmed
-
Open vehicle speed sensor circuit
-
PCM failure
-
TCM failure
Without Electronic Automatic Transaxle
Name of Code:
No Vehicle Speed Sensor Signal
When Monitored:
With engine running more than 31 seconds, engine temperature greater than 180°F, transmission not in park or neutral, brakes not applied, engine
rpm greater than 1,800, and MAP vacuum less than 11".
Set Condition:
No signal from the vehicle speed sensor 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. The PCM supplies 8 volts to power up the sensor. Sensor ground is supplied by the PCM. The PCM also supplies a 5.0
volt pull up voltage to the sensor. The VSS signal is created when the sensor alternates the 5.0 volt pull up from high to low.
Possible Causes:
-
Open or shorted signal circuit
-
Speedometer pinion damaged
-
Open 5-volt supply circuit
-
Open sensor ground circuit
-
Failed vehicle speed sensor
-
PCM failure
-
Connector terminals
-
Connector wires
