Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1993G 10 VAN V6-262 4.3L VIN ZREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSVEHICLE SPEED SENSORDESCRIPTION AND OPERATION
1993 Chevrolet G 10 Van V6-262 4.3L VIN Z
Vehicle Speed Sensor: Description and Operation
1993 Chevrolet G 10 Van V6-262 4.3L VIN ZSECTION Description and Operation
2 Wheel Drive
4 Wheel Drive or All Wheel Drive
PURPOSE
The PCM uses speed information from this sensor to determine the following:
^ Transmission output speed.
^ Vehicle speed.
^ Calculate TCC slip.
OPERATION
The vehicle speed sensor is a magnetic induction type. The vehicle sensor is accessible from the left hand side of the transmission or transfer case near the rear. Voltage is induced in the vehicle sensor by the rotor pressed on the output shaft.
The transmission output shaft. RPM is determined differently for 2WD and 4WD vehicles. On a 2WD vehicle, the vehicle speed sensor is located on the transmission. On a 4WD vehicle, the vehicle speed sensor and the 4WD Lo switch are located on the transfer case. The PCM uses both the transfer case vehicle speed signal and the 4WD Lo switch to determine the transmission output shaft speed. In both applications the vehicle speed sensors send an AC signal to the VSS buffer module which relays 2 digital signals to the PCM. This module converts the VSS into the appropriate miles per hour on one of the signals, then relays it to the PCM.
The PCM uses this speed signal to control engine functions and DTC 16. The other signal is the transmission output speed signal. This signal is buffered b the VSS buffer. This signal is used for shift points, line pressure control, and TCC control.
DTC 24 or 72 will set if a fault exists in the vehicle speed sinsor circuit. When the fault remains and DTC 24 or DTC 72 are set, the PCM will only allow second gear and maximum line pressure to occur. If the fault is removed, normal operation will resume after the next ignition cycle.
VSS 2WD (A/TRANS.) VEHICLE SPEED SENSOR:
4 Wheel Drive or All Wheel Drive
VSS 4WD Or AWD:
PURPOSE
The PCM uses speed information from this sensor to determine the following:
^ Transmission output speed.
^ Vehicle speed.
^ Calculate TCC slip.
OPERATION
The vehicle speed sensor is a magnetic induction type. The vehicle sensor is accessible from the left hand side of the transmission or transfer case near the rear. Voltage is induced in the vehicle sensor by the rotor pressed on the output shaft.
The transmission output shaft. RPM is determined differently for 2WD and 4WD vehicles. On a 2WD vehicle, the vehicle speed sensor is located on the transmission. On a 4WD vehicle, the vehicle speed sensor and the 4WD Lo switch are located on the transfer case. The PCM uses both the transfer case vehicle speed signal and the 4WD Lo switch to determine the transmission output shaft speed. In both applications the vehicle speed sensors send an AC signal to the VSS buffer module which relays 2 digital signals to the PCM. This module converts the VSS into the appropriate miles per hour on one of the signals, then relays it to the PCM.
The PCM uses this speed signal to control engine functions and DTC 16. The other signal is the transmission output speed signal. This signal is buffered b the VSS buffer. This signal is used for shift points, line pressure control, and TCC control.
DTC 24 or 72 will set if a fault exists in the vehicle speed sinsor circuit. When the fault remains and DTC 24 or DTC 72 are set, the PCM will only allow second gear and maximum line pressure to occur. If the fault is removed, normal operation will resume after the next ignition cycle.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.