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) - 2.0L (VIN 1) TBI: Notes
Vehicle speed information is provided to the ECM by the vehicle speed sensor Permanent Magnet (PM) generator mounted in the transaxle. The PM generator produces a pulsing voltage whenever vehicle speed is greater than 3 MPH. The A/C voltage level and the number of pulses increases with vehicle speed. The ECM then converts the pulsing voltage to MPH, which is used for calculations. MPH can be displayed with the "Scan" tester and should match speedometer reading.
- Code 24 will set if vehicle speed equals zero MPH when the following conditions occur:
- Engine speed is between 1400 and 3600 RPM.
- Throttle angle is less than 2 percent.
- Low load condition, low MAP voltage, high manifold vacuum.
- Not in Park or Neutral.
- All conditions met for 5 seconds. These conditions are met during a road load deceleration. Disregard Code 24 that sets when drive wheels are not turning.
- Circuits No. 400, 401 and 993 are okay if the speedometer works properly. Code 24 is being caused by a faulty ECM, faulty PROM or an incorrect PROM.
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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.