How Do You Know Which Tpms Sensor Is Bad

When it comes to maintaining the health of your vehicle, the tire pressure monitoring system (TPMS) plays a crucial role. The primary purpose of the TPMS is to inform you of any significant changes in your tire pressure. However, like any other component of your vehicle, TPMS sensors can malfunction or become faulty over time. In this article, we will explain how to identify which TPMS sensor is bad and provide information on what you can do to address the issue.

Important Outline

1. Understanding TPMS Sensors
2. Common Signs of a Bad TPMS Sensor
3. How to Identify the Faulty Sensor
4. Replacing a Defective TPMS Sensor

1. Understanding TPMS Sensors

TPMS sensors are part of a safety system that monitors your vehicle’s tire pressure in real-time. Driving with incorrect tire pressure can lead to poor fuel efficiency, uneven tire wear, and even blowouts. There are two types of TPMS – indirect and direct. Indirect TPMS relies on the wheel speed sensors. Direct TPMS uses pressure sensors to monitor the exact pressure within each tire. Most vehicles use direct TPMS sensors.

2. Common Signs of a Bad TPMS Sensor

A few symptoms may indicate that one or more of your TPMS sensors are not working properly:

– TPMS warning light: The most apparent sign of a bad TPMS sensor is the TPMS warning light illuminating on your dashboard.
– Inconsistent pressure readings: If your tire pressure readings are continuously fluctuating or inconsistent, this may be a sign that a sensor is faulty.
– Inaccurate tire pressure readings: A bad sensor may provide inaccurate tire pressure readings, leading you to overinflate or underinflate your tires.

3. How to Identify the Faulty Sensor

In most cases, your vehicle’s onboard diagnostic system will help determine which TPMS sensor is faulty. To do this, follow these steps:

1. Plug a TPMS tool or OBD-II scanner into your vehicle’s diagnostics port, usually located under the dashboard on the driver’s side.
2. Turn on your vehicle’s ignition, but do not start the engine.
3. Follow the instructions provided by the TPMS tool or OBD-II scanner to scan for fault codes related to the TPMS.
4. Once you have retrieved the fault code, cross-reference it with the list of TPMS fault codes provided in your vehicle’s manual or online resources.
5. With the fault code information, you should be able to identify which TPMS sensor is faulty and needs to be replaced.

4. Replacing a Defective TPMS Sensor

If you have determined which TPMS sensor is bad, it is best to replace it as soon as possible to ensure the safety and optimal performance of your vehicle. You can either replace the sensor yourself, following the manufacturer’s instructions, or have a professional mechanic do it for you. Keep in mind that after replacing the sensor, you may need to reset the TPMS system to clear the fault code and turn off the warning light.

In conclusion, TPMS sensors are an essential part of your vehicle’s safety system, and it’s crucial to address any issues as soon as they arise. By understanding the common signs of a bad TPMS sensor and using the proper tools, you can easily identify and replace a faulty sensor to keep your tires properly inflated and maintain the overall safety of your vehicle.

Step by Step Guide

In this section, we’ll provide a detailed guide on how to replace a faulty TPMS sensor in your vehicle. Following these steps will help ensure a smooth process and get your vehicle back on the road with a functional TPMS system in no time.

Step by Step Guide with Bullet Points

1. Gather Required Tools and Supplies:
– New TPMS sensor (compatible with your vehicle)
– TPMS tool or OBD-II scanner
– Torque wrench
– Floor jack, jack stands, or ramps
– Tire iron or lug wrench

2. Raise the Vehicle:
– Park your car on a level surface, put it in park or first gear, and engage the parking brake.
– Use a floor jack, jack stands, or ramps to safely raise your vehicle off the ground.

3. Remove the Wheel:
– Use a tire iron or lug wrench to loosen the lug nuts on the wheel corresponding to the faulty TPMS sensor.
– Once the lug nuts have been loosened, carefully remove the wheel from the vehicle.

4. Locate the TPMS Sensor:
– The TPMS sensor is located on the backside of the valve stem. You may need to partially deflate the tire and carefully push the sidewall aside to see and access the sensor.

5. Remove the Faulty Sensor:
– Using the correct TPMS tool, unscrew and remove the sensor from the valve stem while keeping the sensor’s orientation in mind.

6. Install the New TPMS Sensor:
– Place the new sensor in the same orientation as the old sensor and screw it into the valve stem using the TPMS tool.
– Be sure to torque the sensor to the manufacturer’s specifications by using a torque wrench.

7. Inflate the Tire:
– Inflate the tire to the manufacturer’s recommended tire pressure, which can be found on the tire placard located on the driver’s side door jamb, fuel filler door, or owner’s manual.

8. Reinstall the Wheel:
– Place the wheel back onto the vehicle and tighten the lug nuts with the tire iron or lug wrench.

9. Lower the Vehicle:
– Carefully lower the vehicle back onto the ground by using the floor jack, jack stands, or ramps.

10. Reset the TPMS System:
– Plug your TPMS tool or OBD-II scanner into the diagnostics port and follow the instructions to reset the TPMS system.
– Once the TPMS system is reset, the warning light should turn off.

Pros and Cons

Pros of Replacing a Faulty TPMS Sensor:
– Improved safety: Properly inflated tires help maintain optimal vehicle handling, reduce braking distance, and prevent tire blowouts.
– Enhanced fuel efficiency: Correct tire pressure contributes to better fuel consumption, lowering your fuel costs over time.
– Prolonged tire life: Maintaining the right tire pressure can lead to even tire wear, resulting in a longer tire lifespan.

Cons of Replacing a Faulty TPMS Sensor:
– Cost: Purchasing a new TPMS sensor, along with any tools or equipment needed for the replacement, may be an upfront expense.
– Time-consuming: The process of replacing a TPMS sensor can take time, especially if you are not well-versed in automotive repairs.


Q1: How long do TPMS sensors typically last?
A: TPMS sensors usually have a lifespan of approximately 5 to 10 years, but this can vary depending on factors such as weather conditions, temperature changes, and corrosion.

Q2: Can I replace only one TPMS sensor, or do I need to replace all four sensors?
A: You can replace a single faulty TPMS sensor without replacing the others. However, if multiple sensors are showing signs of failure simultaneously, consider replacing all four.

Q3: Does a TPMS sensor replacement require new valve stem attachments or accessories?
A: It depends on the specific TPMS sensor design. Some sensors come with a new valve stem, while others may require the purchase of separate valve stem attachments or accessories.


Maintaining a functional TPMS system is essential for optimal vehicle performance, safety, and longevity. Replacing a faulty TPMS sensor as soon as it has been identified can help you avoid potential dangers and ensure your car’s tires remain correctly inflated. With the provided step-by-step guide, you’ll have the knowledge to replace your faulty TPMS sensor, but if you’re unsure or uncomfortable with the process, always consult a professional mechanic.

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