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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET1992S10/T10 P/U 2WD V6-173 2.8LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSVEHICLE SPEED SENSOR SIGNAL BUFFERDESCRIPTION AND OPERATION
1992 Chevrolet S10/T10 P/U 2WD V6-173 2.8L
Vehicle Speed Sensor Signal Buffer: Description and Operation
1992 Chevrolet S10/T10 P/U 2WD V6-173 2.8LSECTION Description and Operation
The Vehicle Speed Sensor Buffer (DRAC) processes inputs from the Vehicle Speed Sensor (VSS) and outputs signals to the Speedometer, Electronic Control Module (ECM), Cruise Control Module and the Rear Wheel Antilock Brake (RWAL) Module.
The VSS is made up of a 40-tooth rotor and a coil mounted on the transmission. As each rotor tooth nears the coil, the coil produces an AC voltage pulse. Each revolution of the rotor produces 40 AC voltage pulses. As the vehicle speed increases, the number of AC voltage pulses per second increases.
The Vehicle Speed Sensor Buffer (DRAC) takes the voltage pulses from the VSS and uses them to open and close four solid-state output switches to ground at a rate proportional to vehicle speed.
The Speedometer switch opens and closes at the same rate as the VSS pulses. The ECM and Cruise Control switches open and close at half the rate of the VSS pulses. The RWAL switch opens and closes at a rate seven times the VSS pulses.
The Vehicle Speed Sensor Buffer (DRAC) is matched to the vehicle based on transmission, final drive ratio and tire size. It is important to ensure that the correct Vehicle Speed Sensor Buffer (DRAC) is installed in the vehicle if replacement is necessary.
The VSS is made up of a 40-tooth rotor and a coil mounted on the transmission. As each rotor tooth nears the coil, the coil produces an AC voltage pulse. Each revolution of the rotor produces 40 AC voltage pulses. As the vehicle speed increases, the number of AC voltage pulses per second increases.
The Vehicle Speed Sensor Buffer (DRAC) takes the voltage pulses from the VSS and uses them to open and close four solid-state output switches to ground at a rate proportional to vehicle speed.
The Speedometer switch opens and closes at the same rate as the VSS pulses. The ECM and Cruise Control switches open and close at half the rate of the VSS pulses. The RWAL switch opens and closes at a rate seven times the VSS pulses.
The Vehicle Speed Sensor Buffer (DRAC) is matched to the vehicle based on transmission, final drive ratio and tire size. It is important to ensure that the correct Vehicle Speed Sensor Buffer (DRAC) is installed in the vehicle if replacement is necessary.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.