P0500: Vehicle Speed Sensor A Malfunction

Common causes

• A failed vehicle speed sensor (often on the transmission)
• Damaged wiring or a loose, corroded connector
• A faulty ABS wheel speed sensor or ABS module on vehicles that get speed from the ABS system
• A damaged or dirty sensor tone ring

Code meanings can vary slightly by manufacturer. Use these as a starting point and confirm with your vehicle's service information or a mechanic before replacing parts.

Symptoms

• Speedometer that is erratic or stops working
• Harsh, early or late shifting on automatics
• Cruise control not working
• ABS or traction control lights on some vehicles

Is it safe to drive?

Drive gently and get it checked soon: without a speedometer you can't judge your speed, and shifting may be erratic. If the ABS or brake warning light is also on, or the transmission is slipping or stuck in one gear, have it towed or checked before driving further.

How to check it with a scanner

1. Plug an OBD2 scanner into the port under the dashboard and read all stored codes and the freeze-frame data (the conditions when the code set).
2. Scan the transmission and ABS modules too, since their codes often point to the exact sensor.
3. Compare the speed reading in live data with your actual speed (or a phone GPS app, used by a passenger).
4. Inspect the sensor connector and wiring for damage, and check the sensor tip for metal debris.
5. After a repair, clear the code and drive normally for a few days to confirm it doesn't come back.

A basic code reader shows the code; scanners with live data let you watch sensor readings, which is what you need for most of the checks above. See OBD2 scanners under $100.

Questions

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