TPMS Light Flashing? 5 Reasons Why (and How to Fix It!)

Vehicle safety systems are increasingly complex, making dashboard warning lights like the Tire Pressure Monitoring System (TPMS) crucial for alerting drivers to potential issues. A flashing TPMS light, unlike a solid one, often indicates a system malfunction, separate from simply low tire pressure. The National Highway Traffic Safety Administration (NHTSA) mandates TPMS in most vehicles to enhance road safety by preventing accidents caused by underinflated tires. Understanding why your TPMS light is flashing involves troubleshooting potential problems with individual tire sensors or the vehicle's central computer system. Many car owners find themselves asking, why is my TPMS light flashing? and navigating this diagnostic process is key to maintaining vehicle safety and performance.

Image taken from the YouTube channel How to Automotive , from the video titled How To Diagnose A Flashing Tire Pressure Light On A Toyota And Lexus .

Understanding a Flashing TPMS Light: A Detailed Guide

A flashing Tire Pressure Monitoring System (TPMS) light is often more serious than a solid, constantly lit TPMS light. While a solid light generally indicates low tire pressure in one or more tires, a flashing light typically signifies a problem with the TPMS system itself. Let's explore the common reasons why is my tpms light flashing and how to address them.

Initial Troubleshooting Steps

Before diving into the more complex reasons, perform these basic checks first:

• Check Tire Pressure: Visually inspect your tires and use a reliable tire pressure gauge to ensure they are inflated to the manufacturer's recommended pressure (found on the sticker inside your driver's side doorjamb or in your vehicle's owner's manual). Adjust as necessary.
• Drive a Short Distance: Sometimes, the TPMS system needs to recalibrate after a pressure adjustment. Drive for approximately 10-15 minutes to see if the light goes off.

If the flashing light persists after these initial steps, consider the following potential causes.

Reason 1: Sensor Failure

This is the most frequent cause of a flashing TPMS light.

What Happens When a Sensor Fails?

Each tire contains a sensor that monitors tire pressure and transmits the data to the vehicle's computer. Over time, these sensors can fail due to:

• Battery Depletion: TPMS sensors run on batteries, which typically last 5-10 years.
• Physical Damage: Sensors can be damaged by road debris, impacts, or improper tire maintenance.
• Corrosion: Exposure to road salt and moisture can corrode the sensor's internal components.

Identifying a Faulty Sensor

While specialized diagnostic tools are the most accurate method, observing patterns can provide clues:

• Does the light consistently flash immediately upon starting the vehicle?
• Has a specific tire experienced persistent pressure issues despite adjustments?

How to Fix It: Sensor Replacement

Replacing a faulty TPMS sensor is the most common solution. This involves:

1. Having a qualified mechanic or tire technician diagnose the specific sensor causing the issue using a scan tool.
2. Removing the tire from the wheel.
3. Removing the old sensor and installing a new one.
4. Rebalancing the wheel and remounting the tire.
5. Re-programming the new sensor to the vehicle's TPMS system (usually requiring a specialized TPMS tool).

Reason 2: Communication Issues

The TPMS sensors transmit data wirelessly. Interference or a faulty receiver can disrupt this communication.

Potential Sources of Interference

• Radio Frequency Interference (RFI): Strong radio signals from nearby sources (e.g., industrial equipment, cell towers) can sometimes interfere with the TPMS signal.
• Electronic Devices: Certain aftermarket electronic devices installed in the vehicle may cause interference.

Receiver Problems

• Damaged Receiver: The TPMS receiver in your car could be damaged, preventing it from receiving signals from the sensors.
• Wiring Issues: Faulty wiring to the receiver can also disrupt communication.

How to Fix It: Diagnose and Repair the Communication System

Troubleshooting communication issues is best left to a professional. Technicians will use diagnostic tools to:

1. Check for error codes related to TPMS communication.
2. Test the signal strength of each sensor.
3. Inspect the TPMS receiver and its wiring for damage or corrosion.
4. Identify and resolve any sources of RFI.

Reason 3: Incorrect TPMS Sensor ID

When a TPMS sensor is replaced, it needs to be programmed with a unique identification (ID) code that matches the vehicle's TPMS system. An incorrect ID will cause a flashing light.

Common Scenarios Leading to ID Issues

• Improper Programming: If a sensor is not programmed correctly during installation.
• Aftermarket Sensors: Using a generic aftermarket sensor that is not compatible with your vehicle's TPMS system.
• Sensor Swapping: If tires are rotated without also re-programming the TPMS system to account for the new sensor positions.

How to Fix It: Re-programming the Sensors

A qualified technician can use a TPMS scan tool to:

1. Read the current sensor IDs stored in the vehicle's computer.
2. Identify any incorrect or missing IDs.
3. Re-program the sensors with the correct IDs.
4. Perform a relearn procedure, which teaches the vehicle's computer the new sensor positions.

Reason 4: System Malfunction

In some cases, the problem might not be the sensors themselves, but a deeper issue within the vehicle's TPMS system.

Potential Underlying Causes

• Faulty TPMS Control Module: The control module is the brain of the TPMS system. If it fails, it can cause a flashing light.
• Software Glitches: Sometimes, a software glitch can trigger a false TPMS warning.

How to Fix It: System Diagnostics and Repair

Diagnosing a system malfunction requires specialized equipment and expertise. A mechanic will:

1. Use a diagnostic scan tool to check for error codes related to the TPMS control module.
2. Perform a system test to verify the functionality of all TPMS components.
3. Inspect the wiring and connections to the control module for damage or corrosion.
4. Reprogram or replace the control module if necessary.

Reason 5: Recent Tire Changes or Rotations

Any work done on your tires can trigger a TPMS light, especially if the shop wasn’t careful.

Why This Can Happen

• Sensor Damage: Tire technicians might unintentionally damage a sensor during tire removal or installation.
• Failure to Re-program: As mentioned earlier, after a tire rotation, the sensor positions need to be re-programmed into the vehicle's TPMS system.
• Incorrect Installation: If a sensor is not properly installed, it may not function correctly.

How to Fix It: Return to the Tire Shop

The best course of action is to return to the tire shop that performed the work and explain the issue. They should be able to:

1. Inspect the sensors for damage.
2. Verify that the sensors are properly installed.
3. Re-program the sensors to the correct positions.

Video: TPMS Light Flashing? 5 Reasons Why (and How to Fix It!)

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