What causes the tire monitor system light to come on?

The tire monitoring system light (TPMS) comes on mainly when a tire is under-inflated or the system detects a fault. In practice, it can illuminate due to low tire pressure, a bad sensor or control module, or after tire changes and temperature shifts—often requiring inflation checks or a reset.

Common Causes of TPMS Light Activation

Here are the main reasons the TPMS light may illuminate.

• One or more tires are significantly under-inflated relative to the vehicle’s recommended pressure.


• A TPMS sensor or the system’s control module is failing or has a weak battery in the sensor.


• After rotating tires, replacing tires, or working on wheels, the system may need to relearn so sensors map to their rims.


• Significant temperature changes (especially cold weather) can cause tire pressures to drop, triggering the warning.


• A puncture or slow leak in a tire that reduces air over time.


• A tire bead seating issue, damaged valve stem, or wheel damage that causes a pressure leak or sensor misreadings.


• In some models, the spare tire has a TPMS sensor or the system requires a relearn after using the spare.

If the light comes on, start by checking all tires with a reliable gauge and inflate to the manufacturer’s recommended pressure. If the light remains on after correcting pressures, or you notice a tire leak, have the system checked by a technician.

What to Do When the TPMS Light Comes On

Use these steps to respond quickly and safely.

1. Check the tire pressures on all four tires (and the spare, if equipped) with a calibrated gauge. Inflate to the recommended level printed on the door jamb sticker or in the owner’s manual.


2. Inspect tires for obvious damage, cuts, bulges, or punctures; ensure valves and valve stems are intact; check for slow leaks that may require repair.


3. Drive for a short distance to allow indirect TPMS systems to re-measure or direct systems to refresh after inflating; many systems require a few miles of driving.


4. If the light stays on after inflation, consider a TPMS reset/relearn. This may involve a button sequence or scan tool procedure as described in the owner’s manual, or a dealer/independent shop can perform it.


5. If a sensor battery is dead or a sensor is damaged, or if the system continues to report a fault, replace the faulty sensor or repair the system as recommended by a professional.

After completing these steps, monitor the tires and the TPMS light. If it still remains on or comes back after a short time, schedule service to diagnose and repair the TPMS hardware or the tire(s).

Understanding the Light Pattern

Patterns and what they indicate can help prioritize action. The following guidance applies to many vehicles, though exact meanings can vary by make and model.

• A steady TPMS light usually means one or more tires are currently under-inflated. Recheck pressures and drive to allow the system to refresh after inflation.


• A blinking or flashing TPMS light often signifies a system fault or the need for a sensor relearn. In that case, a professional diagnosis with a scan tool is typically required.

Because meanings can differ between vehicles, consult the owner’s manual for the exact interpretation and recommended procedures for resets and relearns.

Practical Takeaway

If you see the TPMS light, start with a pressure check, correct any under-inflation, and drive modestly to allow the system to reset. If the light persists or you notice tire damage, seek professional inspection promptly to prevent unsafe driving conditions.

Summary

The TPMS light signals either under-inflation in one or more tires or a fault within the monitoring system. Common triggers include low tire pressure, faulty sensors or control modules, the need for a relearn after tire changes, and temperature-driven pressure changes. When the light appears, verify pressures, inspect tires for damage, and consult a professional if the light remains on after inflation or follows a system fault pattern. Regular maintenance and timely attention help keep tires safe and the TPMS functioning correctly.

Why is my tire pressure light coming on but my tires are fine?

If your tire pressure light stays on despite your tires being properly inflated, it's likely a problem with the Tire Pressure Monitoring System (TPMS) itself. This could be due to a malfunctioning or dead sensor, a faulty TPMS module, a low-pressure spare tire, or the need for a system reset after adjustment. You should have the system checked by a professional to diagnose and fix the issue. 
This video explains what to do when your tire pressure light stays on: 58sShaners Mechanic LifeYouTube · Apr 7, 2025
Common causes for a persistent TPMS light

• Faulty TPMS sensor: The sensors inside each tire can wear out or become damaged over time from impacts like potholes or hitting curbs. 
• Low-pressure spare tire: If your spare tire has a TPMS sensor and is underinflated, it can trigger the warning light. 
• Need for a system reset: Some vehicles require a manual reset after you have adjusted the tire pressure, or the light may not turn off until you have driven a few miles for the system to recalibrate. 
• Malfunctioning TPMS module: The main computer module that reads the sensors can have electrical or software issues that cause a false alert. 
• Electrical interference: Sometimes, electronic devices can cause interference that leads to a false warning. 

What you can do

1. Double-check all tires: Use a reliable gauge to confirm the air pressure in all four tires is set to the manufacturer's recommended level, which is usually found on a sticker inside the driver's side doorjamb. 
2. Check the spare: Don't forget to check and inflate your spare tire, as it may be the source of the problem. 
3. Drive a short distance: After ensuring all tires are correctly inflated, drive for a few miles. The system may reset itself automatically. 
4. Perform a manual reset: If the light remains on, try to find the TPMS reset button in your vehicle. The location and procedure vary by model, so consult your owner's manual for specific instructions. 
5. Get a professional diagnosis: If the light still won't go off, take your car to a mechanic. They can perform a diagnostic check to find out if a sensor is bad or if there's a problem with the TPMS module. 

How do you fix the tire monitor system?

To fix a tire monitor system, first check and adjust all tire pressures to the recommended PSI, as low pressure is the most common cause. If the light remains on, reset the system using the dashboard controls or reset button, then try driving for a short while to see if the light turns off. If it still doesn't reset, a physical sensor may be damaged or have a dead battery and may need to be inspected, replaced, or reprogrammed by a professional.
 
This video demonstrates how to reset the tire pressure monitoring system (TPMS) light: 53sApple DrainsYouTube · Oct 5, 2012
Step 1: Check and adjust tire pressure 

• Find the correct tire pressure on the sticker on the driver's side door jamb.
• Inflate all tires, including the spare, to the recommended pressure when they are cold (before driving). 

Step 2: Reset the system 

• Turn the ignition to the "ON" position without starting the engine. 
• Find the TPMS reset button on your dashboard or in your vehicle's settings menu. 
• Press and hold the reset button for a few seconds until the light blinks or the system indicates it's ready to relearn. 
• Drive for about 10 minutes; the light should turn off. 

Step 3: Address persistent issues

• Inspect for damage: Check the valve stems and sensors for any visible damage. 
• Replace faulty sensors: If a sensor is damaged or consistently faulty, it will need to be replaced. This is a common problem as sensor batteries typically last 7–10 years. 
• Reprogram sensors: After replacing a sensor, the system may need to be retrained or reprogrammed to recognize the new sensor's ID. This often requires a special TPMS tool. 
• Seek professional help: If you're unable to resolve the issue, take your vehicle to a mechanic. They can use diagnostic tools to find and fix the problem. 

Is it bad to drive with your service tire monitor system light on?

Yes, it is bad to drive with the tire pressure light on because it can lead to poor handling, decreased fuel efficiency, premature tire wear, and a high risk of a tire blowout, which can cause a serious accident. You should check your tire pressure immediately and fill it to the recommended level, which is usually listed on a sticker on the driver's side doorjamb. If the light comes on, it indicates a serious hazard, not just a minor inconvenience. 
Risks of driving with low tire pressure

• Tire failure: Low pressure can cause overheating and stress on the tire, which can lead to a blowout. 
• Poor handling: You may experience reduced steering control and your vehicle's ability to absorb road impacts will be negatively affected. 
• Reduced fuel efficiency: Underinflated tires increase your car's fuel consumption. 
• Uneven wear: Low pressure can lead to premature and uneven wear on your tires. 

What to do if the light comes on

1. Pull over safely: Find a safe place to stop your vehicle. 
2. Check your tires: Visually inspect your tires for any obvious signs of a flat, and use a tire pressure gauge to check the pressure of all four tires. 
3. Inflate tires: If any tires are low, inflate them to the recommended pressure, which can be found on the sticker in the driver's side doorjamb or in your owner's manual. 
4. Check the light again: After inflating, some vehicles may require driving a short distance for the system to reset. 
5. Visit a mechanic: If the light stays on after you've properly inflated your tires, it could indicate a faulty sensor or a slow leak. A professional can properly inspect the TPMS and tires. 

What would cause the service tire monitor system light to come on?

The "Service Tire Monitor System" light comes on due to low tire pressure, a malfunctioning TPMS sensor (including a dead battery), or a problem with the system's control module. It can also be caused by an improperly inflated spare tire or interference from other electronic devices. 
Causes of the warning light

• Low or high tire pressure: The most frequent reason is that one or more tires have a pressure that is too low or too high. This can be caused by: 
  • Normal air loss over time 
  • Small leaks 
  • A significant drop in outside temperature 
  • The spare tire (if it has a sensor) is under- or over-inflated 
• Faulty or dead sensor: A sensor may have failed, become damaged, or have a weak or dead battery. A flashing light that stays on after starting the vehicle often points to a sensor issue. 
• TPMS control module problem: The control module that receives the sensor signals can have an electrical issue, software problem, or wear out over time. 
• System communication issues: The sensors may not have been programmed correctly to communicate with the car's system, or their signals are being disrupted. 
• Recent tire service: The light may come on after a tire rotation or change if the system wasn't recalibrated correctly. 

What to do

1. Check and adjust tire pressure: First, check the pressure in all your tires, including the spare, and inflate them to the manufacturer's recommended PSI. This is typically found on a sticker on the driver's side door jamb. 
2. Address sensor/system issues: If the light stays on after adjusting the pressure, you likely have a sensor or system problem. A blinking light that then stays on is a strong indicator of a system malfunction. 
3. Seek professional diagnosis: Have a mechanic diagnose the issue. They can use a specialized tool to check each sensor and the system's control module to pinpoint the exact problem.