Tire Pressure Monitoring Systems are known as key automotive safety technology essential in every modern vehicle. The system uses sensors to check the air pressure levels on each tire in real-time. By alerting drivers to underinflated tires, they prevent the risk of accidents and ensure safety.
The NHTSA also found that underinflated tires were reduced by 55.6 percent with the help of TPMS. This resulted in tire pressure control systems and sensors becoming an integral part of modern vehicle maintenance. Now, when a car is brought into an auto repair shop, technicians can instantly spot and address underinflated tires before such problems result in a blowout or an expensive tire replacement.
For tire technicians, being able to inspect, repair, and reset TPMS sensors is now a critical skill. Efficiently resolving sensor faults and ensuring that customers leave without warning lights on their dashboards not only reflects technical expertise but also builds trust and lasting customer relationships.
In this guide, we’ll cover what typical tire pressure sensor faults look like and how technicians can address them thoroughly to ensure TPMS sensors are functioning properly.
What does the tire pressure sensor fault mean?
Tire pressure sensors are battery-operated devices. They are embedded in the tires, either in the valve stem or the inner rim. The sensor measures the tire pressure and sends out the information to your vehicle’s TPMS system.
The sensor alerts the TPMS when the tire pressure falls below the manufacturer’s recommended threshold, which then triggers an alert on the dashboard. This system prevents tire pressure from dropping below safe limits and helps drivers address issues before they lead to major problems or tire damage.
Check the vehicle dashboard for warning lights. If the lights are switched on it may be due to these reasons:
1. Faulty TPMS sensor:
If the TPMS light flashes for approximately 60-90 seconds when you turn on your car and stays on. This indicates that the sensor is malfunctioning due to damage in internal components or a dead battery.
2. Changes in temperature:
Low temperatures constrict the air in tires, and high temperatures dilate it. When there are rapid fluctuations in temperature, it causes the TPMS light to turn on and off multiple times. In these cases, the tire pressure sensors are usually working fine, but could indicate poor battery health.
Low tire pressure:
A continuous TPMS light indicates that the tire is underinflated and needs to be inflated. Always check the tire pressure manually to confirm if it needs to be adjusted.
It’s important to keep in mind that sometimes TMPS sensors can send faulty alerts even when the tire pressure levels are normal. This may be due to sensor electronics failure, weak signal strength between sensor and control unit, or issues while resetting the sensors. If the sensors aren’t properly reprogrammed, the TPMS control unit can lose track of their IDs and fail to display accurate pressure data.
Reasons why tire pressure sensors malfunction
In some cases, the lights may come on even when tire pressure levels are normal. This happens when the system shows inaccurate readings or experiences internal faults. In such instances, it’s important to test the TPMS and identify whether the issue lies with the sensors themselves.
Here are some common reasons why tire pressure sensors may malfunction:
Battery failure
TPMS sensors operate on miniature batteries. The typical lifespan of these batteries is between 5 and 10 years. As they weaken or die, the sensors may experience transmission failures or provide faulty readings. For older vehicles, it’s advised to get the sensors’ batteries replaced every five years for better performance.
Physical damage or corrosion
Sensors can be damaged by debris, potholes, or other curbs. The components of the sensors may be corroded in case of additional moisture or road salts. This may provide false tire pressure measurements.
System malfunctions
The TPMS control unit can experience glitches, software malfunctions, or communication delays. This results in false alerts or missed updates, so a diagnostic scan or system reset may be required for the issues to be resolved.
Errors in installation
If your tire service provider skips the relearn or calibration process after tire replacement or rotation, the system may fail to recognize the sensors. This causes delays or errors in transmitting pressure data to the TPMS software.
Frequency issues in the ECU
The TPMS system Electronic Control Unit (ECU) receives data from certain radio frequencies, including the UHF RFID range. The UHF range translates the mechanical signals to electrical signals to be interpreted by the ECU to transmit data to the vehicle receiver. If a different frequency is used, the ECU cannot interpret the signals, preventing it from displaying any tire pressure information.
Interference in radio signals
Metallic window tints or some aftermarket electronic devices can cause disruptions in TPMS radio signals. Tints contain metal particles, which may block radio waves, and electronic devices such as wireless devices or plug-in chargers can cause radio frequency noise.
To minimize such problems, use window films made of carbon or dyed materials that do not block radio waves. If there are TPMS errors during the installation of aftermarket devices, verify whether the device caused the problem.
Shop diagnostics workflow: Tire pressure sensor fault repair
The tire pressure sensors make sure that your tires are inflated, safe, and working well. These sensors are prone to failure after some time. Let’s explore a step-by-step workflow that auto technicians can use to locate the problems with the sensors and correct them:
Step 1: Perform First Scan
When the vehicle arrives at your auto shop, start by running an initial scan using the TPMS diagnostic tool. This will determine whether the sensors are transmitting signals or not.
- If sensors are transmitting signals:
Technicians should use a calibrated gauge to confirm the readings for the level of tire pressure. For instance, the sensor shows 26 PSI, but the gauge, on the other hand, indicates a different level of pressure. This can confirm that there’s an error in the sensor’s transmission.
- If sensors are not transmitting signals:
The sensor may be faulty due to dead or corroded batteries or signal interference. TPMS sensors typically use lithium-ion batteries sealed in epoxy to prevent corrosion and extend lifespan. If a battery has failed, the entire sensor should be replaced.
Step 2: Replace the old or faulty sensor
Remove old sensor
Remove the old TPMS sensor from the valve by unscrewing it using a tire valve stem removal tool. Avoid applying too much pressure so as not to break the stem or the tire.
Install new sensor
Install the new sensor on the valve stem. Tighten manually, then secure with a torque wrench to the required specification by the manufacturer. This is useful for a good seal.
Re-inflate and remount the tire
Fix the tire bead onto the rim using an air compressor. Inflate the tire based on the vehicle’s recommended instructions manual. Install the wheel back on the car again, and tighten the lug nuts in a star pattern.
Step 3: Start diagnosing TPMS system faults
If sensors are functioning correctly but the TPMS warning light is still flashing, the issue may lie in the system itself.
- Connect a TPMS diagnostic tool to the vehicle’s OBD-II port.
- Retrieve and record all fault codes for further analysis. Common examples include:
- C1210: TPMS sensor problem
- C1211: Sensor signal not operating
- C1212: Sensor battery low
- C1213: TPMS communication issue
- Faulty codes can imply damage to the antenna or wiring of the antenna.
- In the event of no signals received, technicians should inspect the wiring and check for signs of short circuits, open circuits, or high resistance that might be causing the issue.
- Do a voltage drop test on the wiring connections. The normal reading should be 0.10 volts or lower. When voltage readings are higher, then the resistance is excessive, and it may affect the signal strength.
Be sure to note that if wiring and antennas are intact, but the system fails to respond, then there may be issues in the ECU. Always verify proper voltage supply and ground connections before replacing the ECU.
Step 4: Relearn sensors and check service history
A complete-service repair will involve viewing tire service records. Technicians should remember to check the time of replacement or rotation of tires. In case of replacement of the tires, the sensors are required to undergo relearning.
Why is relearning important? Perhaps there was a disturbance of sensors during the replacement of tires. Failure to do so may turn out to be erroneous readings and false warnings.
Relearning methods include:
- Manual relearn: A manual way of triggering the sensors is stationary relearning. It is a chain of buttons pressed or an on/off ignition.
- Automatic relearn: Done by operating a vehicle at a minimum speed. This allows the vehicle to automatically detect the new sensor.
- OBD relearn: Requires a diagnostic tool that programs the IDs of the sensors directly into the vehicle’s ECU.
Step 5: Finalize the repair
Technicians are expected to remove all the stored DTCs using a TPMS scanning tool after replacement or sensor relearning. Then run the drive cycle suggested by the manufacturer to the system to clear the system of all of the sensors and reboot itself. Lastly, make sure that the TPMS warning light is no longer blinking so that nothing is left out.
Parts, Labor, and Cost Estimates
For vehicle owners, the cost of replacing tire pressure sensors includes the purchase cost, labor, and time spent on repair.
Here’s a breakdown of what these costs could look like:
- OEM Sensors: $50–$150 each
- Aftermarket Sensors: $25–$75 each
- Labor: 0.3–0.6 hours per sensor, typically under $100 each. May vary a little depending on the type of shop and location
- Programming Fees: $100–$200 per vehicle
Technicians should prepare the following tools and parts for a complete replacement:
- New TPMS sensors
- Valve core remover
- Tire removal tools (jack, lug wrench, tire iron)
- Torque wrench
- TPMS programming tool
Quality Control Checklist
When replacing sensors, there are some quality checks that should be done by the technicians at the end of the exercises.
When replacing sensors, there are some quality checks that should be done by the technicians at the end of the exercises.
- Begin by checking that all sensor IDs are registered with the TPMS ECU.
- Sensor IDs should also be revisited, as the ECU will ignore signals unless they are registered IDs.
- Ensure there are no slow leaks around the new valve stem or seal.
- Make sure torque specifications match the manufacturer’s guidelines.
- Record and document the repair and replacement process for service history.
Tire Pressure Sensor Fault Reset: Procedures and Pitfalls
Oftentimes, relearning and reprogramming are used interchangeably. But these are two different processes.
Reprogramming
Reprogramming is required when new or replacement sensors are installed, especially when using aftermarket or universal sensors. The settings are customized by the technicians so that the sensor adapts to the environment of the vehicle. Consequently, the sensors interact and convey tire data hassle-free.
Once programmed, the sensor can transmit accurate tire data without signal errors.
Relearning
Relearning is done every time a tire is changed, repaired, or replaced. It enables the TPMS control to rediscover sensor IDs and their positions so that the readings correspond to the correct wheel.
Reprogramming or relearning only works on functional sensors. The essence of it is to interface the sensors to the vehicle. It fails to operate with faulty or broken sensors.
Common mistakes when resetting or relearning sensors
Each vehicle has a relearn process, which may be either stationary, OBD, or auto-learn. Following the wrong order will prevent sensors from transmitting their IDs to the vehicle and result with the warning light being on. Always verify the appropriate relearn mode of the vehicle in the vehicle manual or TPMS tool database prior to starting.
Failing to perform a relearn after changing tires can cause the ECU to associate sensor IDs with the wrong wheel positions. This leads to incorrect dashboard readings, such as a “low tire” alert on the opposite side, making future diagnostics more confusing.
The flashing TPMS indicator doesn’t necessarily mean low tire pressure, but could indicate a problem with the communication or system. Pressing the reset or “set” button will only reset the system and not repair a defective battery or a defective transmitter.
Universal (not OEM-specific) sensors may cause problems with programming and signal loss if not accurately configured. Be sure to verify compatibility with the vehicle model before installation.
Applying excessive pressure when screwing on the valve stem, nut, or core may lead to leakage and also damage the sensor. Use a torque wrench according to the specifications of a vehicle to prevent any damages.
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How can car owners fix sensors at home
Some simple steps can be easily carried out by you as a vehicle owner to disable the TPMS light or warnings. These basic measures are often all that is required to ensure tire pressures are normal.
1. Look for a sticker on the driver’s door jamb or the owner’s manual.
2. After confirming the recommended PSI, test the current tires using a tire pressure gauge.
3. Adjust pressure as needed:
- If tires are underinflated, inflate them to the recommended pressure.
- If overinflated, discharge some air until it reaches the point of the appropriate PSI.
- Ensure that the tire pressure is not too low or looks flat. This could be the result of a flat tire and will need professional help.
4. Drive around once the tire pressure is at the right PSI. Maintain the normal speed of 10-20 mph so the TPMS resets on its own, and the lights will flash off on the dashboard.
5. In case the lights don’t go off after the drive, then perform a manual reset.
- Find the reset key, which is normally under the steering wheel.
- Turn on the ignition, but do not start the engine.
- Press the TPMS reset button and hold it until the light flashes a couple of times.
- Release the button and turn on your car. The light should turn off after 20-30 minutes of driving once it is calibrated.
When should you seek a tire technician?
If all the tires are inflated, but the light is still blinking? It is best to have it examined by an expert.
When the light remains on after 90 seconds and turns solid, this usually indicates an issue with the sensors.
A technician can check for sensor battery issues, communication problems, or defective transmitters.
If your dashboard specifically indicates a tire pressure sensor malfunction, professional diagnostics are required to resolve it.
How technology is helping tire shops and technicians
It’s essential for technicians to follow standard procedures and maintain a smooth workflow during TPMS service.
But beyond TPMS systems, tire shops can use shop management tools to keep vehicles in peak condition year-round. While TPMS helps monitor tire pressure, tire shop management software adds another layer of organizational efficiency. From tracking service history, scheduling seasonal tire changes, and ensuring customers get timely maintenance reminders, it helps shops deliver a reliable shop experience so customers feel satisfied with the overall service they receive.
Wrapping up
Tire pressure monitoring systems act as a key safety feature that catches tire issues before they become a bigger hurdle for vehicle owners.
Understanding the mechanism of TPMS and its sensors is critical for technicians so they can accurately address these issues and explain warning signs to customers as well. With proper maintenance, regular sensor checks, and accurate relearn or replacement procedures performed by skilled technicians, ensures safer driving and greater customer confidence.
FAQs
Should a tire pressure sensor fault be used when driving?
It is not recommended to drive with a faulty system, as it will not alert you when you have low pressure or a flat tire, which is a serious safety hazard.
What is meant by tire pressure sensor fault?
It means that there is an issue with the monitoring system. It is not only that a tire has a low pressure level.
Is it possible that the tire pressure sensor will malfunction when tire pressure is okay?
Yes, a dead sensor battery or a damaged sensor are the most common reasons for a malfunctioning sensor.
