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How To Tell Which TPMS Sensor Is Bad

Which TPMS Sensor Is Bad

A sensor is installed in each of your tires called TPMS (Tire Pressure Monitoring System). TPMS is designed to alert you if one or more of your tires are considerably under-inflated, potentially resulting in dangerous driving conditions. So it is important that if you suspect something is faulty — you know how to tell which TPMS sensor is bad. The easiest way to do it is by using a pressure gauge. You can also do it by filling the tires with the recommended pressure and then releasing the air from one tire to another. Observe the display panel and the tire that displays out-of-range message or out of pressure is the one that has a faulty TPMS sensor.

Auto Repairs Are EXPENSIVE


Tire pressure sensors are divided into two categories. The first is a valve type in which the sensor and valve stem are combined into a single unit. The second type of sensor is a band sensor, which is attached to the inside of the rim by a metal band. When the pressure reading is lower than it should be, both sensors illuminate the dash light, alerting the driver to a tire with low air pressure.

How to Tell Which TPMS Sensor is Bad: Why did my TPMS sensor stop working?


When a tire is low, the light should illuminate and then turn off once the low tire has been inflated to its recommended pressure. If the indicator stays on after checking/inflating the tires, or if it flashes and remains illuminated, it could indicate a TPMS issue that has to be diagnosed further.


The following are examples of TPMS issues:


  • The battery in a TPMS sensor has died, and it no longer works.
  • A TPMS sensor that is intermittently functioning due to a failed or weak battery.
  • An antenna or wire issue prevents the TPMS module from receiving a signal from one or more sensors.
  • Because of a voltage supply, wiring, or internal electronics failure, the TPMS module is not working properly or has failed.
  • The tires had recently been serviced or rotated, and the relearn procedure had not been completed correctly.
  • The owner of the car is unaware of how the TPMS system works.


Before doing anything else, you should always use a TPMS tool to activate and check the response signal from each tire pressure sensor in each wheel. This will inform you of: 1) whether each sensor is capable of generating a signal; and 2) whether the pressure measurement is correct if the sensor is capable of generating a signal.


By using a gauge to check the actual pressure in the tire, the pressure reading from a sensor may be easily validated. When you check the pressure with a gauge, if the pressure number reported on your TPMS tool from a sensor is 32 psi, you should find 32 psi.


The importance of calibrating your tire pressure gauge cannot be overstated. The pressures on those inexpensive spring-loaded stick-style tire gauges can vary by up to 5 psi or more. Because many modern digital gauges contain a self-calibrating mechanism that accounts for variations in ambient air temperature, they are the most accurate.


Look for rusted or damaged TPMS valve stems as well. Each wheel's valve stem should be visually inspected for rust or other deterioration that could compromise the valve stem's integrity. When making your diagnosis, keep in mind the vehicle's age and mileage. 


The battery within a brand-new factory TPMS sensor has an average life of seven to ten years, depending on usage. The TPMS sensors emit signals more frequently when the car is driven, and the remaining battery life is depleted faster.


If you discover a TPMS sensor that isn't working or reading correctly, it's natural to assume that the sensor is the source of the problem and that changing it will solve the problem. It usually does. However, there's no way of knowing if a broken sensor is the only issue affecting the system's operation unless you check the rest of the system.


If all of the sensors appear to be in working order and all of the tires are inflated to the proper pressure, but the TPMS warning light remains on or flashes, you'll need to look into the problem further, also by learning how to tell which TPMS sensor is bad and looking at it closely.f


How to Tell Which TPMS Sensor is Bad: What are the symptoms of a faulty TPMS sensor? 


If you suspect a defective sensor, you'll need to know how to tell which TPMS sensor is bad so you are able to replace it. But how will you know if your TPMS sensor is broken? There are various signs or symptoms that you may notice while you drive your car on a daily basis that indicate you have a malfunctioning TPMS sensor. Here are a few:

  • TPMS warning light is on


When your car's computer or ECU (Engine Control Unit) detects a problem with your TPMS sensor, the TPMS light will illuminate. A Tire Pressure Sensor Fault notice may also appear on your dashboard. When you observe the warning light, it is recommended that you go to a service shop. Have a mechanic look at the TPMS warning light to see what's causing it to illuminate.

  • The air pressure in the tires is low


The tire pressure sensor's job is to notify you when the tire pressure is low. If you notice that your tires are flat or that driving your automobile is difficult, the tire pressure sensor has failed or is not functioning properly. To make an accurate assessment, the sensor must be in good working order.


As a result, if no warning indicators appear on your dashboard, you should have the sensor checked by a qualified repair. A Tire Pressure Gauge can be used to check the pressure in your tires.

  • Warnings that are incorrect


If the tire pressure sensor isn't working properly, the DIC may display incorrect alerts. The air pressure in the tires is constantly monitored by TPMS sensors. If they're broken, they can provide the car's computer with false information. This can cause the car's computer to send an alert indicating a problem when there isn't one.


Even if the tire is in perfect condition, the sensor may indicate that it is flat. You could also fix a flat tire and still have it say your tires are still flat. These cautions, on the other hand, should not be taken lightly, as they could lead to future dangerous tire related problems. So if you notice the warnings being sent to you are incorrect you should know how to tell which TPMS sensor is bad — fixing it as soon as possible.

  • The steering wheel is jerky


When the air pressure in your front tires is low, it causes jerky steering. When you have soft, low air pressure front tires, it will be difficult to keep the steering wheel straight and steady. This occurs when a defective TPMS sensor prevents you from receiving an indication that your tires are underinflated.


  • Fuel use has increased


If your tire goes flat while you're driving and you don't realize it because of a faulty TPMS sensor, your car's fuel consumption will increase. This is because driving with a flat tire increases the friction between the tires and the road, requiring more traction to move. The engine will have to use more fuel to compensate for the desired power. As a result, checking your tires and air pressure, whether with or without an illuminated warning sign, is always a smart habit.

Options on How to Tell Which TPMS Sensor is Bad 


Now that you know the symptoms of a faulty TPMS sensor and have seen its symptoms. It’s time to know how to tell which TPMS sensor is bad so you know which one needs urgent repairing or replacing. 


When you see that TPMS warning light on what you must do is drive for a little bit. As the sensor senses new pressure levels, the light should turn off. If the light continues to illuminate, you should have us inspect your tires for a leak or any problem that isn't immediately apparent. If the tire pressure remains constant, the problem could be a faulty sensor and it’s time to detect which one it is. Here are your opinions:

  • Use a TPMS scan reader.


Using a TPMS diagnostic tool or reader, it's straightforward to observe and identify TPMS sensor failures. It can detect a dead or depleted battery, wiring faults, a low voltage source, and many other things.

  • Use a digital pressure gauge.


Using a digital pressure gauge to test the air pressure in all of the tires might also help you discover a defective TPMS sensor. Make a mental note of what you're reading. Compare the pressure gauge readings to the numbers displayed on the dashboard. Any sensor with a different reading is the one that is malfunctioning.

  • Air filling and releasing


This procedure requires patience and time. Check all four tires, fill each with the correct air pressure, then carefully release the air and inspect the vehicle's display panel. If a tire does not deliver a message, it has a faulty sensor that has to be checked or replaced. Make sure the wheel with the faulty sensor is marked, and the remaining tires are filled to the required pressure.

How to Tell Which TPMS Sensor is Bad: Can you replace just one TPMS sensor?


You should now be able to identify which TPMS sensor is malfunctioning. Is it possible to replace just one of your TPMS sensors if one of them fails? Yes, you certainly can. You can replace one of the TPMS sensors if it appears to be defective and has to be replaced. However, it is recommended that if you are replacing one malfunctioning TPMS sensor, you also replace the others. You will save a lot of time and work by doing so. 


If one of your TPMS sensors fails and reaches the end of its useful life, the other sensors may soon follow. That is why, while you're at it, it's a good idea to replace the other sensors as well. The replacement of TPMS sensor batteries and the repair of a rusted valve stem are both examples of this.


Experts also recommended that you reactivate and reset the TPMS sensors each time you change your tires for the season. This is done to ensure that your vehicle's TPMS is working properly.


How much does it cost to replace a TPMS?


If TPMS sensors need to be replaced, the cost can range from $50 to $100 per sensor, depending on the vehicle type. Because TPMS requires additional parts, tools, and labor, TPMS-equipped tires cost slightly more to maintain than non-equipped tires.


When a tire is detached for service or replacement, the TPMS valve service kit, which comprises the valve core, (sealing) cap, nut, and grommet (stem seal), must be replaced. On most automobiles, the servicing kit costs between $5 and $10 per wheel. To inspect and reset the TPMS system, you'll need a specific TPMS programming tool and some extra time.


You can buy a pair of replacement sensors and have them placed in your extra set of tires or wheel assemblies if you have an extra set of tires and wheels for snow tires or custom wheels. Your TPMS installer will be able to relearn the new sensors to the vehicle computer after the extra set of tires or wheel assemblies is fitted to the vehicle. The sensors will need to be relearned to the vehicle computer when the original set of tires or wheel assemblies are reinstalled on the vehicle.


The Tire Pressure Monitoring System has transformed how drivers and car owners think about tire maintenance. The entire system, including the TPMS sensors, have made life easier for them by monitoring tire pressure and alerting them when the tires require maintenance. And it is important to make sure that the system is operating properly. 


Once any symptoms of a faulty TPMS sensor comes up it becomes important how to tell which TPMS sensor is bad. But keep in mind that maintaining your TPMS and its sensors does not replace regular tire checks that you are still advised to do on a regular basis.

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