Fault codeP0500

MODERATE

Vehicle Speed Sensor Malfunction

What this code means

Vehicle Speed Sensor Malfunction.

P0500 is a generic code: it means the same thing on every make. P0500 belongs to family P05xx — Idle speed and vehicle speed control. Its page explains how to read a code and groups all its codes by part.

Vehicle speed sensor

The speed sensor tells the control units how fast the car is going, from the gearbox output or the wheel speed sensors of the ABS. Engine, gearbox, speedometer and cruise control all rely on it.

Symptoms

Speedometer at zero or erratic, cruise control not working, ABS or ESP sometimes in fault, idle hesitating at a standstill and abnormal gear changes on an automatic. The control unit no longer receives the vehicle speed signal.

Common causes

Faulty speed sensor — on the gearbox or, on recent vehicles, derived from the ABS wheel sensors
Damaged sensor connector or loom
Fouled ABS wheel sensor or damaged reluctor
Communication problem between the ABS unit and the engine unit
Worn drive gear on older gearboxes

How to diagnose it

First note whether there are ABS codes: on vehicles where speed comes from the wheel sensors, they name the wheel concerned. In live data, watch the vehicle speed while driving: frozen at zero or jumping, the signal is lost.

Inspect the sensor and its connector, often exposed to spray. Check the resistance or the signal on an oscilloscope.

Watch it live in Klaro

With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:

Vehicle speed
Engine RPM

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →