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.
DTC P0502: VSS Circuit - Low Input (M/T With Abs): Description
Vehicles equipped with M/T with anti-lock brakes receive vehicle speed from a right front wheel speed sensor. Right front wheel speed sensor produces an AC voltage of different amplitude and frequency depending on velocity of right front wheel. Sensor produces a readable AC voltage signal when vehicle speed is more than 3 MPH. Speed signal is sent to the Electronic Brake and Traction Control Module (EBTCM), which converts AC voltage of sensor to a square wave. Square wave is produced by EBTCM grounding White wire from PCM, which is pulled up to 5 volts through a resistor on PCM. DTC sets when PCM does not detect a square wave vehicle speed signal for a certain length of time.
NO RELATED
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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.