Tire Pressure Monitoring Systems (TPMS) are designed to alert drivers via a dashboard icon if one or more tires become underinflated.
However, the system may have a problem if the TPMS light is flashing or a warning message appears.
What does “Tire Pressure Sensor Fault” mean? A tire pressure system fault alert (or flashing TPMS light) most commonly means a sensor has gone bad.
This dashboard warning will also appear if one or more air-pressure sensors are missing. Even low/fluctuating air pressure can occasionally set the system off.
There are two different TPMS types: direct and indirect. This article covers both systems in detail, including how they work, what causes them to fail, and how to fix any issues that arise.
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How Does A Tire Pressure Monitoring System Work?
Direct Tire Pressure Monitoring Systems
Direct tire pressure monitoring systems are by far the most common, as well as the most accurate.
These systems consist of individual air pressure sensors attached to the inner part of each wheel’s rim. Sensors are battery-powered and work by sending readings to a central control module via a radio signal.
Indirect Tire Pressure Monitoring Systems
Indirect systems rely on the ABS system’s wheel-speed sensors to track each tire’s rotational speed and approximate pressure.
Essentially, underinflated tires are smaller in diameter and must turn faster to keep up. Indirect also tends to be more reliable, mostly due to having fewer parts.
What Causes A Tire Pressure Sensor Fault Warning?
Low Tire Pressure
Working correctly, a TPMS will display an alert icon on the dashboard if the air pressure of one or more tires drops below 25% of recommended levels.
It’s not unheard of for the occasional glitch to also cause the TPMS light to flash from low tire pressure.
Fluctuating Outside Temperatures
A tire’s air pressure can fall by about one PSI every 10 degrees the outside temperature drops. If the TPMS light appears after a particularly cold night, you may just need to add some air.
You may even see a tire pressure system fault warning due to fluctuating temperatures.
Tire Pressure Sensor Battery
Tire pressure monitoring sensors are not powered by either a vehicle’s battery or alternator. Instead, they usually run on a three-volt lithium-ion battery that’s good for roughly 10 years or so.
Once drained, a tire pressure monitoring system fault alert should appear on the dash.
System Communication Error
It’s also possible that the sensors and the control module aren’t communicating properly.
A damaged or shorted antenna can cause this, as can bad wiring between the antenna and control module. If a sensor can’t transmit readings, don’t be surprised if “Tire Pressure Sensor Fault” shows up on the dash.
Missing Tire Pressure Sensor
Swapping between summer and winter tires without also transferring the sensors will cause the TPMS light to appear each time you start your vehicle.
Of course, you’ll have to remember the sensors if you exchange the tires yourself. Tire shops will also transfer air-pressure sensors, albeit for an added fee.
How To Fix Tire Pressure Sensor Fault
You won’t cause your vehicle any harm by driving with the TPMS light on.
However, not being alerted to an underinflated tire ups the odds of an accident occurring, making it best to resolve things before they escalate.
What should you do if the message “Tire Pressure Sensor Fault” appears on your car’s dashboard?
Step #1: Check Each Tire’s Air Pressure
If a flashing TPMS light appears, you’ll first need to check each tire’s air pressure and compare it against the recommended PSI found on the tire’s sidewall, adding more if necessary.
Cycle the engine on and off a few times and drive around the block, the indicator should disappear.
Step #2: Manually Reset The TPMS
If all tires are properly inflated, and the TPMS light is still on, you may need to manually reset it.
The process is different between models but can often be done using the driver’s information center/infotainment screen. Some cars require a specific tool and may need brought to a shop.
Step #3: Scan System For Error Codes
Should the TPMS light remain after completing the above steps, you’ll need to plug in a multimeter or OBD2 scanner and then scan for error codes.
Depending on the readings, you’ll likely need to either replace one or more sensors or reprogram/recalibrate the system.
Step #4: Reprogram/Resync The TPMS System
If the error codes reveal the TPMS components aren’t communicating, you may be able to reprogram/resync the system with a good multimeter. Not all units offer this feature, in which case you’ll need to visit a shop to resync the TPMS system.
Step #5: Replace Bad TPMS Sensors
If a sensor’s battery dies, it can’t be replaced, meaning you’ll need to swap the entire unit. Replacing a single TPMS sensor should cost between $150-$200, including labor/diagnostic fees.
Subsequent tires should add $50-$100. Of course, you can also replace TPMS sensors at home to save on fees.
Tire Pressure Sensor Fault: A Good Reason To Check Your Tire’s Air Pressure
A TPMS light, flashing or not, will likely go away once all tires have adequate air pressure. However, if not, you’ll need to act if you want the system to be able to alert you of a low tire.
Ignoring a TPMS indicator may not harm your car, but an underinflated tire can quickly become a road hazard.
There are many different types of sensors, including those to measure oxygen, fluid levels, and even fuel temperature. Check out this in-depth guide for a full rundown of all the different sensors in a car.