A Complete Guide to Tire Pressure Monitoring Systems (TPMS)
Key Takeaways
- TPMS monitors tire pressure and alerts drivers when it drops below the recommended level to improve safety and efficiency.
- There are two types of TPMS: direct TPMS uses sensors inside tires for accurate readings, while indirect TPMS relies on wheel speed sensors.
- Common TPMS warnings occur due to low tire pressure, faulty sensors, battery failure, or system malfunctions.
- Regular tire pressure checks, sensor replacements, TPMS resets, and proper maintenance ensure accurate readings and system longevity.
What is a Tire Pressure Monitoring System (TPMS)?
A Tire Pressure Monitoring System (TPMS) is an electronic system that continuously monitors the air pressure inside a vehicle’s tires and alerts the driver when the pressure falls below the recommended level.
Why is TPMS Important?
- Prevents Accidents: Proper tire pressure ensures better traction and reduces the risk of blowouts.
- Improves Fuel Efficiency: Underinflated tires create more rolling resistance, increasing fuel consumption.
- Extends Tire Lifespan: Correct tire pressure prevents uneven wear, increasing the longevity of tires.
- Enhances Vehicle Handling: Properly inflated tires improve braking and overall driving performance.
Types of Tire Pressure Monitoring Systems
There are two main types of TPMS:
Direct TPMS
Direct TPMS (dTPMS) uses pressure sensors inside each tire to measure air pressure and send real-time data to the vehicle’s onboard computer.
How Direct TPMS Works
- Sensors mounted inside each tire measure air pressure and temperature.
- The data is transmitted wirelessly to the TPMS control module.
- If the pressure drops below the recommended level, the TPMS warning light on the dashboard illuminates.
Advantages of Direct TPMS
✔️ Provides accurate and real-time pressure readings.
✔️ Can detect pressure loss in individual tires.
✔️ Works independently of tire size or type.
Disadvantages of Direct TPMS
❌ Sensors require battery replacement after a few years.
❌ More expensive to install and maintain.
❌ Reprogramming may be needed after tire replacement.
Indirect TPMS
Indirect TPMS (iTPMS) does not use pressure sensors. Instead, it relies on the vehicle’s Anti-lock Braking System (ABS) and wheel speed sensors to detect changes in tire pressure.
How Indirect TPMS Works
- When a tire loses pressure, its diameter decreases, causing it to rotate faster than other tires.
- The wheel speed sensors detect this discrepancy and send a warning signal to the TPMS module.
- The TPMS light turns on when a significant difference in wheel rotation is detected.
Advantages of Indirect TPMS
✔️ Less expensive compared to direct TPMS.
✔️ No sensor batteries to replace.
✔️ Works well with different tire brands and sizes.
Disadvantages of Indirect TPMS
❌ Less accurate than direct TPMS.
❌ Cannot measure actual tire pressure, only detects relative changes.
❌ Requires recalibration after tire rotation or replacement.
How to Identify a TPMS Warning Light
When TPMS detects low tire pressure, a yellow warning light shaped like a tire cross-section with an exclamation mark appears on the dashboard.
Common TPMS Warning Signs
- Steady TPMS Light: Indicates at least one tire has low pressure.
- Flashing TPMS Light: Suggests a malfunction in the TPMS system, requiring inspection.
Common Causes of TPMS Warnings
Low Tire Pressure
Tires naturally lose pressure over time due to changes in temperature or small air leaks. Cold weather can cause pressure to drop quickly, triggering the TPMS warning light.
Faulty TPMS Sensors
TPMS sensors typically last between 5-10 years before they wear out. When a sensor stops working, it can send incorrect signals or fail to detect low tire pressure.
Battery Failure in Direct TPMS Sensors
Direct TPMS sensors rely on small built-in batteries that eventually run out. When the battery dies, the sensor stops transmitting data, leading to a TPMS warning light.
Tire Rotation or Replacement Without Resetting TPMS
Some vehicles require TPMS recalibration after tire rotation or new tire installation. If not reset, the system may give inaccurate readings or keep the warning light on.
Electrical Issues in the TPMS Module
A malfunction in the TPMS control unit can prevent sensors from sending pressure data. Wiring issues or software glitches may also cause false warnings or system failure.
How to Fix TPMS Warnings
Check Tire Pressure
Use a reliable tire pressure gauge to check the PSI of all four tires. If the pressure is low, fill each tire to the manufacturer’s recommended level to turn off the TPMS warning light.
Reset the TPMS System
Many vehicles have a TPMS reset button, usually located under the dashboard or in the glove box. Hold the button until the TPMS light blinks, which signals that the system has been recalibrated.
Replace Faulty Sensors
If the TPMS light stays on even after inflating the tires, one or more sensors may be faulty. A tire shop can diagnose the issue and replace any malfunctioning sensors if needed.
Inspect the TPMS Module
A malfunctioning TPMS control unit can cause false warnings or system failure. A professional mechanic can inspect and repair electrical faults to restore proper TPMS function.
Maintaining Your TPMS for Long-Term Use
Regularly Check Tire Pressure
Even with TPMS, manually checking tire pressure once a month ensures accuracy. A tire pressure gauge helps detect slow leaks or minor pressure drops before they trigger a warning.
Replace TPMS Sensors When Needed
Most direct TPMS sensors have a battery life of 5-10 years and will eventually stop working. Replacing them on time prevents false alerts and keeps the system functional.
Keep the TPMS System Calibrated
After tire rotations or new tire installations, the TPMS system may need recalibration. Follow the vehicle manual to reset the system and ensure accurate pressure readings.
Avoid Harsh Driving Conditions
Hitting potholes, rough roads, or curbs at high speeds can damage TPMS sensors inside the tires. Driving carefully on uneven surfaces helps extend sensor lifespan.
Use Compatible Tires
Some aftermarket or oversized tires may not work well with TPMS sensors. Before purchasing new tires, check compatibility to avoid TPMS errors or malfunctions.
Frequently Asked Questions
Can I Drive With the TPMS Light On?
Driving with a TPMS warning light is unsafe. Check tire pressure immediately to prevent accidents.
How Much Does It Cost to Replace TPMS Sensors?
Replacing a TPMS sensor costs between $50-$250 per sensor, depending on the brand and labor costs.
Can I Install TPMS in a Car That Doesn’t Have It?
Yes, aftermarket TPMS kits are available and can be installed by a mechanic.
Do All Cars Have TPMS?
Since 2007, TPMS has been mandatory in all passenger vehicles sold in the U.S. However, older cars may not have it.
Does Cold Weather Affect TPMS?
Yes, tire pressure decreases in cold weather, often triggering TPMS warnings. Checking and adjusting pressure in winter is essential.
Conclusion
A Tire Pressure Monitoring System (TPMS) is a vital safety feature that enhances vehicle performance, fuel efficiency, and tire lifespan. Understanding its functions, common issues, and maintenance practices ensures a safer and more efficient driving experience.
If your TPMS warning light appears, always inspect tire pressure promptly. Regular maintenance and timely sensor replacements will keep your TPMS functioning optimally.
By keeping your tire pressure in check, you not only enhance vehicle safety but also save money on fuel and tire replacements.