Common Reasons Why the TPMS Light is On

5 min readJul 27, 2023


The Tire Pressure Monitoring System (TPMS) light is a warning indicator on your car’s dashboard. It is designed to alert you when there is a problem with the air pressure in one or more of your tires. Since the handling and performance of your car can be negatively impacted by having the wrong tire pressure, this can be a serious safety concern.

So, why is your TPMS light on? There are several common reasons this may happen, and this blog post will explore some of these reasons. By understanding the possible causes, you can take the necessary steps to fix the problem and ensure your vehicle is safe to drive.

Photo Credit: Ricardo Figueiredo

Low Tire Pressure

Low tire pressure is a common issue that can lead to the illumination of the Tire Pressure Monitoring System light in our vehicles. Underinflated tires are often the culprit behind this warning signal. When the tire pressure drops below the recommended level, it can affect our vehicle’s overall performance and safety. The TPMS light serves as an early warning system, alerting us to potential problems with tire pressure.

The tire pressure sensor inside each tire continuously monitors the air pressure. When it detects that one or more tires have low pressure, it sends a signal to the vehicle’s onboard computer, which triggers the TPMS light to illuminate the dashboard. Driving with underinflated tires can have several negative consequences. It may result in decreased fuel efficiency, reduced traction and handling capabilities, increased risk of blowouts or punctures, and uneven wear. Therefore, it is crucial to address low tire pressure promptly.

Faulty TPMS Sensor

A faulty Tire Pressure Monitoring System sensor can cause inconvenience and potential safety risks for drivers. When the sensor malfunctions, it can trigger the warning light on the dashboard, indicating a problem with tire pressure. There are several reasons why a TPMS sensor may malfunction. It could be due to a low battery, damage to the sensor itself, or even interference from other electronic devices. Regardless of the cause, it is crucial to address the issue promptly to ensure accurate tire pressure monitoring.

When faced with a faulty TPMS sensor, replacement is often necessary. A qualified technician can diagnose the problem using a TPMS diagnostic tool. This tool allows them to identify which specific sensor is causing the issue and determine if it needs repair or replacement. Replacing a faulty TPMS sensor involves removing the old one and installing a new one compatible with your vehicle’s make and model. It is important to note that attempting to replace or repair TPMS sensors without proper knowledge and tools can lead to further complications or unreliable readings.

Tire Replacement or Rotation

When it comes to tire replacement or rotation, it’s essential to understand how these actions can affect the Tire Pressure Monitoring System light in your vehicle. When you replace a tire, especially if it’s a different size or type than the original one, like off-road truck tires, the TPMS may need to be recalibrated. It is because the system relies on specific measurements and parameters set for each tire and wheel combination. If you replace a tire without recalibrating the TPMS, it may not accurately monitor the tire pressure and trigger the TPMS light.

Similarly, rotating your tires from one position to another can also affect the TPMS. In some cases, the system may need to go through a relearning process for the TPM sensors to detect and monitor each tire’s pressure properly. Following manufacturer guidelines and consult with professionals when replacing or rotating tires is crucial. They can ensure that proper recalibration or relearning processes are performed on your vehicle’s TPMS, minimizing potential issues with the system and ensuring optimal safety on the road.

Battery Issues

A weak or dead battery can significantly impact the functionality of the Tire Pressure Monitoring System in your vehicle. The TPMS relies on sensors powered by the vehicle’s battery to monitor tire pressure levels accurately. When the battery is weak, it may not provide enough power to sustain the sensors’ operation. It can result in inaccurate readings or a complete failure of the TPMS system. In such cases, you may receive false alerts about low tire pressure or no warnings, putting you at risk of driving with underinflated tires.

Incorrect Sensor Placement

Sensor placement is crucial for the Tire Pressure Monitoring System to function effectively. Sensors are typically installed inside each tire, either on the valve stem or as a part of the tire’s inner liner. They constantly monitor tire pressure and send signals to the vehicle’s onboard computer system.

However, if sensors are improperly placed or not aligned correctly, they may fail to detect tire pressure fluctuations accurately. It can result in false readings being sent to the TPMS light on your dashboard, leading to confusion and potentially compromising your safety on the road. Improper sensor installation can occur for various reasons, such as inexperienced technicians, improper handling during tire replacements or repairs, or even accidental damage during routine maintenance procedures.

Faulty Wiring or Connectors

Electrical problems can often be the culprit behind the Tire Pressure Monitoring System light that remains illuminated. One potential cause of this issue is faulty wiring or connectors within the system. When the wiring or connectors become damaged, the communication between the sensors and the control module can disrupt, leading to a persistent TPMS light.

Damaged wiring harnesses are a common source of electrical issues in vehicles. Over time, these harnesses can suffer wear and tear, exposing wires to elements that may cause them to fray or break. When a wire responsible for transmitting data from the sensors to the control module is affected, it can result in an inaccurate reading and trigger the TPMS warning light.

In addition to damaged wiring harnesses, loose connections with sensors or control modules can contribute to an illuminated TPMS light. Vibrations from driving or other external factors may cause connections to become loose over time, disrupting proper signal transmission. As a result, the control module may not receive accurate information regarding tire pressure levels and trigger an alert on your dashboard.

Cold Weather Effects

When temperatures drop, the air inside the tires contracts, causing a decrease in tire pressure. Generally, for every 10-degree Fahrenheit decrease in temperature, tire pressure can drop by approximately 1–2 pounds per square inch (PSI). It means that tire pressure can significantly decrease during cold weather conditions compared to warmer weather. In cold weather, it is common for drivers to see the TPMS light illuminate due to reduced tire pressure caused by temperature changes. It serves as a reminder to check and adjust the tire pressure accordingly.

Proper Maintenance is the Key

Regular attention to your tires for maintenance and upkeep should be a top priority; this is a key factor that contributes towards safer journeys and maximizes the overall lifespan of your ride. Situations like driving on flat tires or failing to monitor your tire pressure can cause dangerous situations or significant damage to our vehicles. Ultimately, by taking proactive steps like using TPMS systems to monitor our tires and scheduling periodic maintenance visits, we can ensure our safety and savings in the long run.

With the proper precautions and knowledge, all drivers can benefit from improved safety and smoother journeys.




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