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.
Vehicle Speed Sensor (VSS): Description
The function of vehicle speed sensor is to sense the TOOTH signal in T/M housing (4 pulses are output per 1 turn) and send relevant signal to ECM. The signal is used for computing the vehicle speed and the speed display on the tachometer as well.
The information is used for idle control correction duty range (the range of correction is limited with the vehicle speed and A/C load), cooling fan control, fuel injection prohibition at over vehicle speed, vehicle jerk control and traction control (At the torque being reduced with the exhaust gas modeling).
The action against malfunctions of the sensor is to fix the speed at 0 KPH. (The highest engine revolution should be limited to 2500 RPM).
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.