2021 Toyota Prius Tire Pressure Warning Light Stays On

Tire Pressure Warning Light in 2021 Toyota Prius: Causes and Solutions

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
40% chance it's the
Tire Leaking Air
0%
30% chance it's the
Wheel Leaking Air
0%
15% chance it's the
Tire Pressure Monitoring System
0%
15% chance it's
Something else
The most common reasons a 2021 Toyota Prius tire pressure warning light stays on are a leaking tire, a wheel that no longer holds air, or a faulty tire pressure monitoring system.
  • Tire Leaking Air: A puncture, valve stem issue, or rim damage can cause a tire to leak air, leading to loss of pressure.
  • Wheel Leaking Air: A puncture or damage to the tire or rim can cause air to leak, resulting in a loss of tire pressure.
  • Tire Pressure Monitoring System: A malfunctioning tire pressure monitoring system can be caused by faulty sensors or a dead battery in the sensor units.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2021 Toyota Prius tire pressure warning light stays on?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

When a tire pressure monitoring sensor fails, the tire pressure monitoring system control module will recognize a loss in communication and turn on the warning lamp which indicates the failure. This is most often the case. However, the tire pressure monitoring sensor may also fail by reporting incorrect tire pressures. This could cause a flat tire to go unrecognized, or a properly inflated tire to signal a low or high tire pressure warning.

When a relearn is needed, for any reason, the TPMS warning light will illuminate, and many vehicles will display a message relating to the TPMS system being inoperative or loosing communication. It is important to keep a watchful eye on tire pressures when this system is having issues because there is no warning available for underinflation or overinflation of the tires.

Wheels offer very few symptoms, but these symptoms should never be ignored. Visible cracks on the wheels may appear, especially after hitting a large bump, Most often, this will also be accompanied by loss of air from the tire on that wheel. Also, vibration in the steering wheel is very common when the tire is out of balance, and improper wheel nuts or bolts can cause creaking and popping noises to develop. Again, there are very few symptoms, but they should not be ignored.

The only symptoms requiring diagnosis for the tire pressure monitoring system warning lamp is if the warning lamp has illuminated while the tires have correct air pressure, or if the air pressure for the tires is out of specification and the warning lamp is off. This is because the overwhelming majority of cases where the TPMS lamp illuminates is due to the change in ambient temperature.

What steps should I take to diagnose the tire pressure warning light issue on my 2021 Toyota Prius?

To effectively diagnose the tire pressure warning light issue on your 2021 Toyota Prius, begin with a thorough check of the tire pressure in all four tires using a reliable tire pressure gauge. Ensure that each tire is inflated to the recommended levels outlined in your owner's manual, as improper inflation is a common trigger for the warning light. Next, inspect the tires for any visible damage, such as punctures, cuts, or bulges, which could indicate a more serious problem. If the tires appear to be in good condition, consider resetting the tire pressure monitoring system, as temporary fluctuations can sometimes cause the warning light to activate unnecessarily. Additionally, examine the valve stems for any signs of damage or leaks, as faulty valve stems can also lead to pressure issues. If, after completing these steps, the warning light remains illuminated, it may be time to consult a mechanic or dealership for a comprehensive inspection and diagnosis, ensuring your vehicle remains safe and roadworthy.

What could be causing the tire pressure warning light to remain on in my 2021 Toyota Prius?

When the tire pressure warning light stays on in your 2021 Toyota Prius, it’s essential to understand the potential causes to address the issue effectively. One of the most common culprits is low tire pressure, which can result from natural air loss or changes in temperature. Regularly checking and maintaining the recommended tire pressure is vital for ensuring both safety and optimal fuel efficiency. If the tire pressure is adequate, the problem may stem from a faulty tire pressure sensor that could require replacement. Additionally, sensor calibration issues might arise, necessitating a recalibration to ensure accurate readings. Electrical malfunctions within the tire pressure monitoring system can also trigger the warning light, often requiring diagnostic testing to pinpoint the specific issue. Environmental factors, such as extreme temperatures or driving over rough terrain, can temporarily affect tire pressure, so it’s wise to reassess your tire pressure after such conditions. By addressing these issues promptly, you not only enhance your vehicle's performance but also ensure your safety on the road. If the warning light remains illuminated despite your troubleshooting efforts, it’s advisable to consult a professional mechanic or visit a Toyota dealership for a thorough inspection and resolution.

How urgent is it to address the tire pressure warning light that stays on in a 2021 Toyota Prius?

Addressing the tire pressure warning light in your 2021 Toyota Prius is not just a matter of convenience; it is a critical safety issue that demands immediate attention. When this warning light remains illuminated, it signals that your tires may be underinflated, which can severely compromise your vehicle's handling and braking capabilities. This lack of proper tire pressure can lead to dangerous driving conditions, increasing the likelihood of accidents. Furthermore, neglecting this warning can result in uneven tire wear, which not only shortens the lifespan of your tires but can also lead to costly replacements. Additionally, underinflated tires can significantly reduce your fuel efficiency, causing you to spend more on gas over time. By promptly checking and adjusting your tire pressure, you ensure that your Prius operates safely and efficiently, ultimately protecting both your investment and your well-being on the road.

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