How to Fix Code P0501: What It Means and How to Repair It

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When trouble codes trigger the Check Engine Light, we are left anxious and confused. But don’t fret, as these codes don’t necessarily mean your car needs a major repair; it could be something as simple as a loose or faulty connection.

In this article, we will take a look at one of the most common codes: P0501. We’ll explain what it means, how to diagnose and repair it, and why it’s important to do so. Stay tuned!

What is Code P0501?

The P0501 error code is triggered when information sent by the Vehicle Speed Sensor (VSS) is outside of the expected range. The VSS is an electromagnetic sensor that connects to the PCM by completing an input circuit. This sensor is found in a car’s transmission housing. 

When the Powertrain Control Module (PCM) or the Engine Control Module (ECM) receives data output from the VSS, which indicates that the system has a variable voltage output causing instability, the P0501 is triggered. 

Symptoms of Code P0501

Aside from an illuminated check engine light, drivers may experience a few symptoms in their vehicles. These can include:

  • The transmission shifting is causing the engine to lose power.
  • The speedometer may work, but it may jump up and down while reading too low or high compared to           the vehicle's actual road speed.
  • Shifting may be rapid or sluggish, depending on whether the VSS signal is negative or positive.

Causes of Code P0501

P0501 is related to several other trouble codes that deal with the VSS, such as P0500, P0502, and P0503. If not for an OBD scanner, determining which one is which would definitely be confusing. Here are some of the common causes of this error code:

  • Faulty cables or connections to the VSS sensor
  • Damaged speed sensor vehicle
  • The VSS required voltage is not in place as it bounces up or down more quickly than the PCM anticipates.
  • The output of the VSS voltage is lower than expected, and the output speed of the actual vehicle speed            limit is lower than average.
  • A transmission or differential gear, which powers many VSS, may be damaged. Any gear may produce an      inconsistent VSS signal if teeth are fractured. The need for a transmission VSS to be replaced or repaired        might be required.
  • Incorrect PCM setup for the size of the car tires.

How to Diagnose Error Code P0501

As we always say, you won't be able to know the issue if you will not diagnose the code first. If you arent sure about doing that, don't worry, as we've got you covered! Here is a step-by-step guide to diagnosing the P0501 code.

Step-by-Step Guide

  1. Use the OBD scanner tool to scan any and all codes and save them in the ECM.
  2. Using a GPS signal or another car, measure the VSS signal while driving at consistent speeds to see                  whether the speedometer is accurate within a few miles per hour.
  3. Inspect the VSS electrical connection for loose or corroded connections
  4. Remove the VSS, check for metal particles at the sensor's tip, clean, and test for proper functioning.

How to Fix Code P0501?

After doing all the steps above and you still experience the P0501 code, you may try several fixes to clear the code. Please remember that repairing this problem yourself will not guarantee the issue to be resolved. 

So if you're not comfortable doing it, take your car to a professional and have them diagnose and repair the problem. However, if you are confident in your automotive abilities, here are some possible solutions:

  • Replace or clean the VSS sensor
  • Check and replace electrical connectors.
  • Reprogram ECM computer if all else fails.

Common Mistakes When Diagnosing the P0501 Code

Every diagnosing process is prone to mistakes. Many people are jumping to conclusions without properly inspecting the entire system. Some of the most common mistakes when diagnosing the P0501 code are:

  • Not verifying all connections and parts before beginning repairs.
  • Not using the correct tools or parts for the job.
  • Assuming that the problem is with the sensor and not another part of the vehicle.
  • Not checking for other codes that may be associated with P0501.
  • Not verifying other causes before replacing the VSS.
  • Not removing and checking if the VSS has excessive metal particles that might be causing a problem and weak signal with internal transaxle or rear axle components.

Code P0501 FAQs

1. Is the P0501 Code Serious?

The code P0501 usually indicates a decrease in the speedometer reading, which you may not take seriously. However, the code can also be triggered by a faulty VSS or with another part of the vehicle's transmission or rear axle. These could cause transmission damage and erratic shifting, so you should have this repaired as soon as possible.

2. Can I drive with this error code?

If the P0501 code is intermittent, you may be able to continue driving your vehicle. However, if the code becomes constant, it is recommended that you have the problem diagnosed and repaired as soon as possible.

3. How soon do I need to address the issue?

If the P0501 code is causing your vehicle to run poorly, you should address the issue as soon as possible. If the code does not cause any problems with how your car runs, you can wait until later to have it repaired, but we recommend having it fixed as soon as possible.

4. How much does the repair cost?

It may vary depending on the severity of the problem and the parts that need to be replaced. However, you can expect to pay between $200 and $500 for a professional repair.

5. Is it necessary to use an OBD scanner in diagnosing?

It is unnecessary to use an OBD scanner to diagnose the P0501 code in most cases. However, if you cannot find the problem after inspecting the car's wiring and connectors, using a scanner can help pinpoint the issue.


Trouble codes can be incredibly frustrating and often leave us concerned about what’s going on with our car. The P0501 code is not a very serious issue, but we urge you to address it as soon as possible. If your car has been giving you trouble, you can fix this yourself or send your vehicle to a professional mechanic.

We hoped we could help you diagnose and repair the P0501 error code. If you have questions regarding the P0501 error code, please contact us through the comments below. Thank you for reading.