Have you ever had that frustrating moment when your tire pressure warning light pops up on your dashboard, but you just can’t seem to figure out which TPMS sensor is causing the problem? Well, fear not! In this blog post, we’ll be discussing how to tell which TPMS sensor is bad? and save you from having to replace all of them. So grab a cup of coffee and let’s dive in!
What is TPMS?
A TPMS, or tire pressure monitoring system, is a sensor that helps to ensure that your tires are inflated to the proper pressure. These sensors can be located in the tire itself, or the wheel. If one of your TPMS sensors is not working properly, it can cause your vehicle to handle poorly and may lead to a flat tire.
How to Tell Which TPMS Sensor Is Bad?

Here’s a detailed guide on how to tell which TPMS sensor is bad:
Step 1: Check the TPMS Warning Light
The first thing you should do is check the TPMS warning light on your dashboard. If the light is on, it indicates that there’s a problem with the tire pressure in one or more of your tires. Typically, the warning light will also indicate which tire is affected. This can help you narrow down which TPMS sensor is bad.
Step 2: Use a TPMS Tool
If the warning light doesn’t indicate which tire is affected, you can use a TPMS tool to identify the bad sensor. A TPMS tool is a device that can communicate with the TPMS sensors in your tires and provide you with information about their status.
To use a TPMS tool, follow these steps:
- Turn on the TPMS tool and select the “diagnostic” or “scan” mode.
- Place the tool near each tire and wait for it to detect the sensor.
- Once the tool has detected the sensor, it will display information about its status, including the tire pressure, temperature, and battery level.
- Repeat this process for each tire until you’ve identified the bad sensor.
Step 3: Check the Battery Level
If the TPMS tool indicates that a sensor has a low battery level, it may be the cause of the problem. TPMS sensors typically have a battery life of around 5-7 years, so if your vehicle is older than that, the battery in one of the sensors may have died.
To check the battery level of a TPMS sensor, follow these steps:
- Remove the tire from the wheel.
- Locate the TPMS sensor on the inside of the tire.
- Use a multimeter to check the voltage of the sensor’s battery. The voltage should be around 3 volts.
- If the voltage is significantly lower than 3 volts, the battery needs to be replaced.
Step 4: Inspect the Sensor for Damage
If you’ve ruled out a low battery as the cause of the problem, the sensor may be damaged. TPMS sensors can be damaged by impacts or exposure to extreme temperatures.
To inspect a TPMS sensor for damage, follow these steps:
- Remove the tire from the wheel.
- Locate the TPMS sensor on the inside of the tire.
- Inspect the sensor for any visible damage, such as cracks or corrosion.
- If the sensor is damaged, it needs to be replaced.
In summary, to tell which TPMS sensor is bad, you can check the TPMS warning light, use a TPMS tool, check the battery level, and inspect the sensor for damage. By following these steps, you can identify the bad sensor and replace it to ensure that your vehicle is running safely and smoothly.
What to Look For When Assessing TPMS Sensors?

When assessing TPMS (Tire Pressure Monitoring System) sensors, there are a few things you should look for to ensure that they’re functioning properly. Here are some key things to look for when assessing TPMS sensors:
- Battery Life: TPMS sensors are battery-powered, and they typically have a lifespan of around 5-7 years. When assessing TPMS sensors, you should check the battery life to make sure that it’s not low or dead. You can use a TPMS tool to check the battery level of each sensor.
- Signal Strength: TPMS sensors communicate with the car’s computer using radio waves. When assessing TPMS sensors, you should check the signal strength to ensure that it’s strong enough to transmit accurate data. A weak signal can result in inaccurate readings or no readings at all.
- Pressure Accuracy: TPMS sensors are designed to monitor tire pressure and alert you when it falls below a certain level. When assessing TPMS sensors, you should check their pressure accuracy to ensure that they’re providing accurate readings. You can use a tire pressure gauge to compare the readings from the TPMS sensors with the actual tire pressure.
- Temperature Range: TPMS sensors are designed to operate within a specific temperature range. When assessing TPMS sensors, you should check the temperature range to ensure that it’s appropriate for your vehicle’s operating conditions. Extreme temperatures can affect the accuracy of TPMS readings.
- Physical Condition: TPMS sensors are exposed to a lot of wear and tear, as they’re located inside the tire. When assessing TPMS sensors, you should check their physical condition to ensure that they’re not damaged or corroded. Damaged sensors should be replaced to ensure that they function properly.
By assessing TPMS sensors for these key factors, you can ensure that they’re functioning properly and providing accurate readings. If you notice any issues with your TPMS sensors, it’s important to address them promptly to ensure your safety on the road.
The Three Types of TPMS Sensors
There are three types of TPMS sensors: direct, indirect, and hybrid. Direct TPMS sensors use a pressure sensor to measure the air pressure in the tire. Indirect TPMS sensors use a speed sensor to measure the rotational speed of the wheel. Hybrid TPMS sensors use both a pressure sensor and a speed sensor to measure the air pressure and rotational speed of the wheel.
How to Diagnose a Bad TPMS Sensor?
A TPMS sensor is used to monitor the air pressure in your tires. If the sensor detects a low-pressure reading, it will trigger a warning light on your dashboard. There are a few different ways to test whether or not a TPMS sensor is working properly.
One way to test the sensor is by using a tire pressure gauge. Simply check the pressure in all four tires and compare the readings to what the TPMS sensor is showing on your dashboard. If the two readings match, then the sensor is likely working properly.
Another way to test the sensor is by using a handheld TPMS device. These devices can be found at most auto parts stores and are relatively easy to use. Simply place the device next to each tire and follow the instructions on the screen. The device will show you whether or not each sensor is working properly.
If you suspect that one of your TPMS sensors is not working properly, it’s important to have it checked out as soon as possible. Driving with low tire pressure can cause premature wear and tear on your tires and may even lead to a blowout.
Conclusion
Knowing how to tell which TPMS sensor is bad can be a valuable skill, especially if you are a car owner. With the right tools and knowledge, you can identify faulty sensors and have them replaced to prevent further damage or problems with your vehicle’s performance. If you ever encounter any issues related to tire pressure monitoring system sensors, make sure that you take it up with an automotive specialist who has experience dealing with TPMS.
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