P0501 Vehicle Speed Sensor Malfunction

Understanding the Vehicle Speed Sensor Malfunction: Causes, Symptoms, and Solutions

Driving is an essential part of our daily lives, and without a functional vehicle, it can be challenging to navigate through our daily routine. One crucial component of a vehicle that plays a significant role in ensuring its smooth operation is the Vehicle Speed Sensor (VSS).

The VSS is responsible for measuring the speed of the vehicle and transmitting this information to the Engine Control Module (ECM).

However, a malfunctioning VSS can cause a wide range of issues that can affect not only the performance of the vehicle but also its safety. In this article, we will discuss the causes, symptoms, and solutions of a VSS malfunction and how to diagnose and fix it.

Causes of Vehicle Speed Sensor Malfunction:

The VSS can malfunction due to various reasons, including:

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  1. Damaged Wiring: Wiring issues are one of the most common causes of VSS malfunction. Damaged, corroded, or broken wiring can cause a loss of signal, leading to a malfunctioning VSS.
  2. Failed Sensor: The VSS is an electronic component that can fail over time due to wear and tear. A failed sensor can cause inaccurate speed readings, leading to various issues.
  3. Faulty Connectors: Faulty connectors can cause a loss of signal, leading to a malfunctioning VSS. This is mostly caused by corrosion or dirt buildup, which blocks the connection between the sensor and the ECM.

Symptoms of Vehicle Speed Sensor Malfunction:

A malfunctioning VSS can cause various symptoms that can affect the vehicle’s safety and performance:

  1. Inaccurate Speedometer Reading: The speedometer reading can be inaccurate or fail to work altogether. This means that the driver may not know how fast the vehicle is traveling, which can be dangerous.
  2. Harsh Shifting: The transmission may shift harshly or erratically, making it difficult to drive the vehicle smoothly.
  3. Check Engine Light: A malfunctioning VSS can trigger the check engine light to come on. This means that there is an issue with the VSS, and the vehicle should be checked by a mechanic.

Diagnosing Vehicle Speed Sensor Malfunction:

Diagnosing a malfunctioning VSS requires a basic understanding of the vehicle’s electrical system. Here are the steps to diagnose a VSS malfunction:

  1. Check the wiring: Inspect the wiring leading to the VSS for any damage, corrosion, or breaks.
  2. Check the connector: Check the connector between the VSS and the ECM for any dirt or corrosion buildup. Clean the connector if necessary.
  3. Test the VSS: Use a digital multimeter to test the VSS’s resistance. If it fails the test, replace the sensor.

Solutions to Vehicle Speed Sensor Malfunction:

Depending on the cause of the malfunctioning VSS, here are some solutions to fix the issue:

  1. Repair Damaged Wiring: Replace any damaged wiring leading to the VSS.
  2. Replace Failed Sensor: If the VSS sensor has failed, replace it with a new one.
  3. Clean Faulty Connectors: If the connector is dirty or corroded, clean it with a connector cleaner.


A malfunctioning Vehicle Speed Sensor can cause various issues that can affect the vehicle’s performance and safety. However, by understanding the causes and symptoms of a VSS malfunction, it is possible to diagnose and fix the issue. Regular maintenance and inspection of the vehicle’s electrical system can help prevent VSS malfunction and ensure the vehicle’s smooth operation.


  1. Can a malfunctioning VSS cause the transmission to slip?
    Yes, a malfunctioning VSS can cause harsh and erratic shifting, leading to transmission slipping.
  2. How much does it cost to replace a faulty VSS?
    The cost of replacing a faulty VSS varies depending on the make and model of the vehicle. However, on average, it can cost between $100 to $300.
  3. Can a malfunctioning VSS cause the ABS light to come on?
    Yes, a malfunctioning VSS can cause the ABS light to come on as it affects the operation of the ABS system.
  4. Can a faulty VSS affect fuel economy?
    Yes, a malfunctioning VSS can affect the vehicle’s fuel economy by causing inaccurate speed readings, leading to incorrect fuel consumption measurements.
  5. How often should the VSS be inspected?
    It is recommended to inspect the VSS during routine maintenance, i.e., every 30,000 to 50,000 miles, or as per the manufacturer’s recommendation.