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P0500

Vehicle Speed Sensor A Circuit.

  • Generic
  • Powertrain
  • Generic code
  • Medium severity

How this code is built

P
SystemPowertrain
0
Defined bySAE, the same on every car
5
AreaVehicle speed, idle control and auxiliary inputs
00
FaultThe specific fault in that area

What it means

P0500 is the generic code for a fault in the Vehicle Speed Sensor A circuit. The engine control unit has seen a missing, implausible or erratic vehicle speed signal, for example no speed reading while engine load and rpm suggest the car is moving. Depending on the vehicle, the signal may come from a dedicated sensor, from wheel speed sensors via the ABS module, or over the CAN bus.

Symptoms

  • Speedometer reads zero, drops out or behaves erratically
  • Check engine light on, possibly with ABS or traction control warnings
  • Cruise control or speed limiter not working
  • Harsh, delayed or incorrect gear changes on automatics
  • Poor idle control or stalling when slowing to a stop
  • Transmission stuck in limp mode or a single gear

Possible causes

  • Faulty vehicle speed sensor or wheel speed sensor (worn, contaminated or failed internally)likely
  • Damaged wiring or poor connector contact in the speed sensor circuit (corrosion, chafing, water ingress)likely
  • Damaged or dirty sensor reluctor ring or tone wheel, or metallic debris on a magnetic sensor tippossible
  • ABS module or instrument cluster fault affecting the speed signalpossible
  • CAN bus communication fault preventing the speed signal reaching the engine control unitpossible
  • Worn or damaged sensor drive gear in the gearbox or differential, where fitted (model dependent)rare
  • Internal transmission control unit fault or software issuerare

How to diagnose

  1. Read all stored codes and freeze frame data, noting whether ABS, transmission or CAN communication codes are also present
  2. Check whether the speedometer works and compare live vehicle speed data with actual road speed on a safe test drive
  3. Compare live wheel speed values from the ABS module to see if one wheel or all are missing a signal
  4. Visually inspect the sensor, wiring and connectors for damage, corrosion, moisture or chafing, and check the sensor is properly seated
  5. Check the sensor tip and reluctor or tone ring for debris, damage, missing teeth or excessive air gap
  6. Test the sensor circuit for supply, earth and signal using the manufacturer's wiring diagram and specifications
  7. Check the CAN bus network for faults and test communication between the ABS module, cluster and engine control unit
  8. If the sensor is driven by a gear, inspect the drive gear for wear or damage as directed by model-specific procedures

How to fix

  • Replace the faulty vehicle speed or wheel speed sensor
  • Repair or replace damaged wiring and clean or replace corroded connectors
  • Clean or replace the damaged reluctor ring or tone wheel and correct the sensor air gap
  • Repair the CAN bus fault found, or repair or replace the faulty control unit or cluster
  • Replace a worn sensor drive gear, where fitted
  • Clear the codes after repair and road test to confirm the fault does not return

Can I keep driving?

Medium severity

The car can usually be driven short distances, but an inaccurate speedometer is a legal and safety concern, and ABS or gearbox behaviour may be affected. Get it fixed soon, and avoid it if the gearbox is in limp mode or ABS warnings are showing.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

This code for other makes

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