How do I know if my Toyota TPMS sensor is bad?

If your Toyota's Tire Pressure Monitoring System (TPMS) is malfunctioning, it's important to diagnose and address the issue promptly. A bad TPMS sensor can lead to inaccurate tire pressure readings, which can compromise your vehicle's safety and fuel efficiency. In this article, we'll explore the signs of a faulty TPMS sensor and provide steps to help you determine if it needs to be replaced.

Signs of a Bad TPMS Sensor

Here are some common indicators that your Toyota's TPMS sensor may be malfunctioning:

• TPMS Warning Light: If the TPMS warning light on your dashboard is illuminated, it's a clear sign that the system has detected an issue with one or more of the tire pressure sensors.


• Inaccurate Tire Pressure Readings: If the tire pressure readings displayed on your vehicle's information screen or dashboard are consistently different from the actual tire pressure, it could indicate a problem with the TPMS sensor.


• Frequent TPMS Warnings: If you're constantly receiving TPMS warnings, even after inflating your tires to the recommended pressure, it may be a sign of a faulty sensor.


• Sensor Failure: In some cases, the TPMS sensor itself may fail, leading to a complete loss of tire pressure monitoring functionality.

If you notice any of these issues, it's important to have your Toyota's TPMS system inspected by a qualified technician to determine the root cause and the appropriate course of action.

Diagnosing a Bad TPMS Sensor

To diagnose a faulty TPMS sensor, your technician will typically follow these steps:

• Scan for TPMS-related trouble codes: Using a diagnostic tool, the technician will scan your vehicle's computer system for any TPMS-related trouble codes, which can provide valuable information about the specific issue.


• Inspect the TPMS sensors: The technician will physically inspect the TPMS sensors, checking for any signs of damage, corrosion, or other issues that could be causing the malfunction.


• Test the TPMS sensors: If the sensors appear to be in good condition, the technician may use a TPMS tool to test the sensors' functionality and ensure they are transmitting accurate tire pressure data.


• Replace the faulty sensor(s): If the TPMS sensor is determined to be the source of the problem, the technician will replace the faulty sensor(s) to restore proper TPMS operation.

By following these diagnostic steps, your Toyota technician can accurately identify and address any issues with your vehicle's TPMS sensors, ensuring your tires are properly monitored and your vehicle is operating safely.

How do you know if your TPMS sensor is bad?

You can tell a TPMS sensor is bad if the TPMS warning light stays on or flashes after you start the car. Other signs include inaccurate or fluctuating tire pressure readings, a failure to reset the light after inflating tires, or physical damage to the sensor from impacts like hitting a curb. A dead sensor battery is a common reason for failure, and the entire sensor usually needs to be replaced when the battery dies.
 
Common signs of a bad TPMS sensor

• Persistent TPMS light: The most direct sign is the TPMS warning light on your dashboard that either stays on constantly or flashes for a minute or two before staying on. 
• Inaccurate tire pressure readings: A sensor may report an incorrect pressure, such as showing a tire is underinflated when it's not, or the readings might jump around erratically. 
• Failure to reset: If the TPMS light stays on even after you've inflated all your tires to the correct pressure, a sensor may be faulty. 
• Physical damage: A sensor can be damaged from hitting curbs, potholes, or other road hazards. Look for visible damage to the valve stem or sensor body. 
• Handling issues: Low tire pressure from a bad sensor can cause steering to feel tight or heavy, as the engine has to work harder. 
• Reduced fuel efficiency: Underinflated tires increase rolling resistance, leading to poorer fuel economy. A bad sensor that fails to warn you can contribute to this problem. 

How to diagnose a bad sensor

• Check tire pressure first: Always inflate your tires to the manufacturer's recommended pressure to rule out a simple underinflation issue. 
• Use a TPMS scan tool: A professional TPMS scan tool can diagnose which sensor is bad by reading its status. You can get your car scanned at an auto parts store or a mechanic. 
• Use a diagnostic scanner: An OBD-II scanner can often identify a faulty sensor with a specific error code. 
• Manually test sensors (on some vehicles): For some car models, there's a manual procedure involving a sequence of button presses to trigger the system and identify a failing sensor. 

How to tell which TPMS sensor is bad on a Toyota?

You can tell which TPMS sensor is bad on a Toyota by using a TPMS diagnostic tool to communicate with each sensor and see which one is not responding or is showing an error, or by using an OBD2 scanner that can read live TPMS data, which may show a sensor is sending a false low-pressure reading. A tire shop can also perform this diagnosis for you using their specialized tools. 
You can watch this video to see how a TPMS tool is used to find a bad sensor: 59sAuto Repair GuysYouTube · Jun 15, 2022
Method 1: Use a TPMS diagnostic tool 

• This is the most direct method and is performed by a tire shop or a professional mechanic. 
• The tool is held near each tire's valve stem to communicate with the sensor. 
• The tool will show information like tire pressure, sensor ID, and battery status for each wheel. 
• A sensor is likely bad if the tool cannot connect to it, if the pressure reading is incorrect, or if it fails to "wake up" when triggered. 
• Some tools can also be used to put the car into a "program mode," and the one that doesn't beep or respond is the faulty one. 

Method 2: Use an OBD2 scanner 

• Connect the scanner to the vehicle's OBD2 port.
• Access the live data stream for the TPMS system.
• The scanner will display the pressure reading from each sensor.
• A bad sensor will often show a pressure of zero or an incorrect value while the tire is properly inflated.
• The scanner may also provide a specific trouble code (like C1503) that indicates which sensor is at fault. 

This video demonstrates how to use an OBD2 scanner to identify a bad TPMS sensor: 51sBudget MechanicYouTube · Mar 22, 2025
Method 3: Take it to a professional

• A tire shop has the necessary specialized tools to diagnose TPMS issues.
• They can accurately identify the faulty sensor and replace it for you.
• Many shops can perform the diagnosis and replacement for a reasonable price. 

How long do Toyota TPMS sensors last?

Toyota TPMS sensors typically last 5 to 10 years or 70,000 to 120,000 miles before the internal battery dies, requiring the entire sensor unit to be replaced. It's often recommended to replace all four sensors at once, especially when changing tires, since if one fails, the others will likely fail soon afterward.
 
Factors affecting lifespan

• Driving habits: More driving can lead to a shorter lifespan due to more frequent radio frequency transmissions from the sensors. 
• Time and mileage: The sensors are battery-powered, so their lifespan is limited by both time and usage. 
• Damage or wear: Factors like physical damage or worn-out seals can cause a sensor to fail prematurely. 

When to replace them

• Replace them preemptively: It's good practice to replace them when they reach the end of their lifespan (around 7-10 years) or when you get new tires. 
• Replace them when one fails: If one sensor fails, it's best to replace all of them since the others are likely near the end of their life as well. 
• Note: The entire sensor unit must be replaced when the battery fails, as the batteries are not designed to be replaced separately. 

How do you test a Toyota TPMS sensor?

Front. Going to repeat the process hold the TPMS tool fairly close to the uh valve stem here and we're going to hook go ahead and hit test. So it's triggering the sensor trying to activate it.