The P0500 OBD2 code indicates a malfunction with the vehicle speed sensor. The first symptoms most drivers notice are on the dash. The speedometer may read erratically, or not record speed at all. Several warning lights may also activate, including the check engine light and ABS light.
While a faulty vehicle speed sensor isn’t likely to cause damage to your engine, it can make driving difficult. A lot of safety features found in modern cars rely on VSS to operate properly. Problems with the vehicle speed sensor are most hazardous when driving on wet or icy roads.
P0500 is a generic powertrain code, applicable to any engine with an OBD2 diagnostic system. Having said that, the most common repair does differ between manufacturers. It’s a good idea to check before starting repairs to see if there are any known fixes for your vehicle.
P0500 Code Definition
Vehicle Speed Sensor “A” Malfunction
What does P0500 mean?
The vehicle speed sensor (VSS) is how your car knows how fast it’s currently traveling. It sends data to the powertrain control module (PCM) or engine control module (ECM) to help it maintain optimal operation.
The VSS is an electromagnetic sensor, traditionally mounted on the transmission housing. A reluctor ring attached to the transmission shaft passes the tip of the VSS on each rotation. These interruptions to the circuit are translated into the vehicle speed and output to the ECM or PCM.
The exact location of the VSS varies widely between manufacturers. It’s typically found on or near the transmission system on rear-wheel-drive vehicles. It may also be located inside a wheel well or attached to the speedometer. In many modern engines, there is a speed sensor on each wheel. Check your manual before you start making repairs to find out the configuration of your engine.
The data from the VSS is displayed on the speedometer on the vehicle dash. It’s also shared with the transmission system, power steering, and anti-lock brake system (ABS), so malfunctions in this sensor can have wide-ranging effects.
Other trouble codes related to the speed sensor include P0501, P0502, and P0503. You may see one or more of these codes along with P0500, especially if the sensor itself is malfunctioning.
What are the symptoms of the P0500 code?
There are often no noticeable drivability symptoms with P0500 aside from erratic speedometer readings. The extent of issues largely depends on how your engine’s systems use the data from the vehicle speed sensor. Common symptoms include:
- Activation of the check engine light
- Activation of ABS dash warning light
- Speedometer or odometer not working properly
- Disabling of ABS or traction control systems
- Difficulty shifting or erratic shifting from the automatic transmission
What are the causes of P0500?
- Faulty vehicle speed sensor
- Faulty speedometer
- Damaged or loose wires around VSS
- Opens or shorts in wiring harness
- Damaged electrical connections
- Damage to drive gear
- Communication issues in the engine computer
- PCM or ECM not configured to current tire size
How serious is the P0500 code?
The P0500 code is of moderate severity. Your ability to drive won’t be impeded while this code is active, but the vehicle may have difficulty shifting or can lose crucial safety systems like anti-lock brakes and traction control. In addition, it will be difficult to maintain proper driving speed without a functional speedometer. You should take care of driving your vehicle with a P0500 code active, especially in rainy or wintery weather.
How to diagnose and fix the P0500 code
Tools you’ll need:
- OBD2 scan tool
- Digital multimeter
- Check for any technical service bulletins related to the P0500 code for your vehicle. There are known fixes for this problem for many vehicles, most notably Toyotas. Following suggestions for your specific make and model can greatly speed the diagnostic process.
- If you’ve recently replaced your tires, verify that they are the same size that you had on the vehicle before. Different sized tires rotate at different speeds relative to the engine speed, and your engine computer needs to be updated to compensate. Take your vehicle to a mechanic to have your ECM or PCM configured correctly for the actual size of the tires on your vehicle.
- Use an OBD2 scanner to read all trouble codes and look at the freeze frame data. Check the readings from the VSS for the most recent drive cycle. If the signal is intermittent, there is likely a wiring issue.
- Visually inspect the wires around the VSS and speedometer. Replace any that are frayed or otherwise damaged, and make sure all connections are clean and secure. If you made any repairs or adjustments, clear the code and re-scan.
- If the VSS readings are erratic but you found no damaged wires, use a multimeter to test each wire for internal shorts or open circuits.
- Use a multimeter to test the voltage of the vehicle speed sensor. Compare the readings to the specifications in your repair manual and replace it if necessary.
- Malfunctions in other electronic components, such as the speedometer, can interrupt communication between the VSS and the engine computer. A mechanic can verify if this is the case by checking the sensor waveform and making the necessary repairs.
Common mistakes to avoid while diagnosing the P0500 code
You may be tempted to replace the speedometer when you see it’s not working, but in most cases, the P0500 code is caused by a faulty sensor or faulty wiring. Make sure you conduct a thorough diagnosis before making repairs to avoid unnecessarily replacing functional components.
Tips to avoid P0500 in the future
The most preventable cause of the P0500 code is a failure to reprogram the ECM or PCM after replacing the tires. Even a small change in tire diameter can cause erratic readings from the vehicle speed sensor. While some OBD2 scanners allow you to make these modifications yourself, in most cases you’ll want to take your vehicle to a mechanic to have the computer re-configured after replacing your tires.
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