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.
Code 24, Vehicle Speed Sensor (VSS) Circuit: Notes
ECM provides 5 volts to a reed switch inside speedometer at instrument panel. This signal voltage is varied, depending on speed of drive wheels. If ECM does not sense this varying voltage signal for about 3.5 seconds, Code 24 is set.
- Checks to see if problem is intermittent.
- If VSS is not receiving 5 volts from ECM, Code 24 will set. This step checks for an open or short to B+ in the Yellow wire or for a faulty ECM.
- This checks for a poor ground connection, an open in the Black/Yellow wire or for a faulty VSS.
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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.
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