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)
The transmission-mounted VSS sends a pulsing signal to PCM when vehicle is moving. The VSS generates pulses with axle shaft revolution. The PCM interprets speed sensor input along with TP sensor closed throttle input.
This input enables PCM to differentiate between closed throttle deceleration and closed throttle idle (vehicle stopped) conditions. During deceleration, PCM controls Idle Air Control (IAC) valve to maintain a desired manifold pressure. During idle, PCM controls IAC motor to maintain a desired idle speed.
NO RELATED
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.