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 Circuit: Notes
ECM supplies a B+ signal to Vehicle Speed Sensor (VSS). While vehicle is moving, a reed switch inside VSS will open and close, toggling B+ signal high and low. ECM then converts this toggled high/low voltage into a vehicle speed that is displayed as MPH/KPH.
Code 24 will set if a constant voltage signal (high or low) is not detected at ECM for at least 4 seconds, with engine running and vehicle moving.
- Checks if problem is intermittent.
- If VSS is not receiving 12 volts from ECM, Code 24 will set. Checks for open in Yellow/Green wire or a faulty ECM.
- Checks for a poor ground connection, an open in Black/Blue wire or a faulty VSS.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no 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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.