What does P0502 mean?
The vehicle speed sensor reports how fast the vehicle is moving. The engine computer, transmission, speedometer and cruise control may all use it.
The signal is below the expected range, usually a wiring or sensor fault.
Codes are a starting point. They tell you which test failed, not which part to replace. Check for other stored codes and fix those in a sensible order.
Symptoms
- Speedometer not working or jumping
- Erratic or harsh shifting
- Cruise control not working
- ABS or traction lights (on some vehicles)
Common causes
- Signal wire shorted to ground
- Damaged sensor
- Unplugged or corroded connector
How to diagnose P0502
- Inspect the connector and harness.
- Check the signal and its ground with a meter or scope.
- Test or replace the sensor once the wiring checks good.
- Watch vehicle speed in live data while driving (with a helper).
- Inspect the sensor and remove any metal debris.
How to fix it
- Replace the speed sensor
- Repair wiring
Estimated repair cost
Likely repairs for P0502 run from about $150 to $350, depending on the cause.
| Repair | Typical range (parts + labor) |
|---|---|
| Diagnostic fee (scan + testing) | $100 - $200 |
| Vehicle/transmission speed sensor | $150 - $350 |
These are rough US estimates for an independent shop in 2026, based on typical parts prices and standard labor times. Dealers, big trucks, luxury brands and high-cost areas often run higher. They are not quotes. Use the repair cost estimator to adjust for your vehicle.
How serious is P0502?
Moderate severity
Usually drivable, but shifting may be harsh and the speedometer unreliable.
P0502 FAQ
What does P0502 mean?
P0502 stands for "Vehicle Speed Sensor "A" Circuit Low Input". The vehicle speed sensor reports how fast the vehicle is moving.
Can I drive with a P0502 code?
Usually drivable, but shifting may be harsh and the speedometer unreliable.
How much does it cost to fix P0502?
It depends on the cause. The likely repairs for P0502 range from about $150 to $350 at an independent shop in the US, plus a diagnostic fee of roughly $100-$200. These are rough estimates; dealer prices and some vehicles run higher.
What is the most common cause of P0502?
The most common causes are: signal wire shorted to ground; damaged sensor; unplugged or corroded connector.