A Tire Pressure Monitoring System (TPMS) sensor is a crucial component in modern vehicles, responsible for monitoring the air pressure in each tire and alerting the driver when the pressure falls below a safe level. However, like any electronic device, TPMS sensors are susceptible to various types of failures, which can lead to inaccurate readings, warning lights, and even safety concerns. In this comprehensive guide, we will delve into the common causes of TPMS sensor failure, the signs to look for, and the steps you can take to diagnose and fix the issue.
Common Causes of TPMS Sensor Failure
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Low Battery Voltage: TPMS sensors are powered by non-replaceable lithium-ion batteries, which have a lifespan of around 5-10 years. As the battery ages and loses its charge, the sensor may start to provide inaccurate readings or fail to transmit data to the vehicle’s computer, triggering the TPMS warning light.
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Battery Voltage Range: Typical TPMS sensor batteries operate within a voltage range of 2.5V to 3.3V. When the voltage drops below 2.5V, the sensor may start to malfunction.
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Battery Capacity: TPMS sensor batteries typically have a capacity of 600-900 mAh, depending on the manufacturer and model.
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Damage from Road Debris: The TPMS sensor is located on the valve stem of each tire, making it vulnerable to damage from road debris such as rocks, potholes, and other objects. Physical damage to the sensor can cause it to become dislodged, disconnected, or even completely destroyed, leading to TPMS system failure.
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Sensor Mounting Torque: TPMS sensors are typically installed with a torque of 4-8 Nm (3-6 ft-lb) to ensure a secure fit on the valve stem.
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Sensor Diameter: TPMS sensors come in various diameters, typically ranging from 11 mm to 14 mm, to fit different valve stem sizes.
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Exposure to Extreme Temperatures: TPMS sensors are designed to operate within a specific temperature range, typically from -40°C (-40°F) to 125°C (257°F). Exposure to temperatures outside this range can damage the sensor’s electronic components, leading to inaccurate readings or complete sensor failure.
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Operating Temperature Range: The optimal operating temperature range for TPMS sensors is -40°C (-40°F) to 125°C (257°F).
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Storage Temperature Range: TPMS sensors should be stored in a temperature range of -40°C (-40°F) to 85°C (185°F) to prevent damage to the internal components.
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Corrosion: TPMS sensors can be susceptible to corrosion, especially in areas with high exposure to salt, moisture, or other corrosive materials. Corrosion can damage the sensor’s electronic components and lead to communication issues or sensor failure.
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Corrosion Resistance: TPMS sensors are typically made of materials that are resistant to corrosion, such as stainless steel or aluminum, but they can still be affected by prolonged exposure to harsh environments.
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Sensor Sealing: TPMS sensors are designed with seals to protect the internal components from moisture and other environmental factors, but these seals can degrade over time, leading to corrosion.
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Sensor Age: TPMS sensors have a limited lifespan, and as they age, they become more prone to failure. Over time, the sensor’s internal components can wear down, leading to inaccurate readings or the TPMS warning light coming on.
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Sensor Lifespan: Most TPMS sensors are designed to last for 5-10 years, depending on usage and environmental conditions.
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Sensor Replacement Interval: Vehicle manufacturers typically recommend replacing TPMS sensors every 5-10 years or when the sensor’s battery life is depleted.
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Faulty Wiring: In some cases, TPMS sensor failure can be caused by damaged or disconnected wiring, which can prevent the sensor from transmitting accurate information to the vehicle’s computer.
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Wiring Harness Integrity: TPMS sensors are connected to the vehicle’s wiring harness, which can be susceptible to damage from road debris, corrosion, or improper installation.
- Wiring Resistance: The resistance of the TPMS sensor wiring should be within the manufacturer’s specified range, typically less than 5 ohms.
Signs of TPMS Sensor Failure
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TPMS Light Flashing: If the TPMS warning light on the dashboard starts flashing after the initial bulb check and continues to flash, it is a clear indication of a failing TPMS sensor.
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Inconsistent Readings: If the tire pressure readings displayed on the vehicle’s instrument cluster or infotainment system are inconsistent or do not match the actual tire pressure, it may be a sign of a faulty TPMS sensor.
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Low Battery Warning: Some TPMS systems are equipped with the ability to detect low battery levels in the sensors and will display a warning light or message to alert the driver.
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Sensor Identification Issues: In some cases, the vehicle’s TPMS system may have trouble identifying or communicating with a specific sensor, leading to warning lights or error messages.
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Sensor Malfunction Codes: TPMS-equipped vehicles will store diagnostic trouble codes (DTCs) when a sensor failure is detected, which can be read using a diagnostic tool or scanner.
Diagnosing and Fixing a Faulty TPMS Sensor
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Check the Battery Voltage: Use a multimeter to measure the voltage of the TPMS sensor’s battery. If the voltage is below 2.5V, the battery will need to be replaced.
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Reprogram the Sensor: In some cases, reprogramming the TPMS sensor can resolve issues with inaccurate readings or warning lights. This process typically involves using a TPMS programming tool or following the vehicle manufacturer’s recommended procedure.
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Reset the TPMS System: Resetting the TPMS system can sometimes clear any stored diagnostic trouble codes and resolve issues with inaccurate readings or warning lights. This process may involve using a diagnostic tool or following the vehicle manufacturer’s recommended procedure.
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Replace the Sensor: If the TPMS sensor is physically damaged, corroded, or has reached the end of its lifespan, it will need to be replaced. This typically involves removing the old sensor, installing a new one, and programming it to the vehicle’s TPMS system.
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Sensor Replacement Cost: The cost of a TPMS sensor replacement can vary depending on the vehicle make and model, but it typically ranges from $50 to $150 per sensor.
- Sensor Replacement Procedure: The process of replacing a TPMS sensor usually involves removing the tire, accessing the valve stem, and following the vehicle manufacturer’s recommended installation and programming procedures.
Technical Specifications
- Battery Life: 5-10 years, depending on usage and environmental conditions.
- Operating Temperature Range: -40°C (-40°F) to 125°C (257°F).
- Frequency: 315 MHz or 433 MHz radio frequency signal.
- Sensor Diameter: 11 mm to 14 mm, to fit different valve stem sizes.
- Sensor Mounting Torque: 4-8 Nm (3-6 ft-lb).
- Sensor Battery Capacity: 600-900 mAh.
- Sensor Battery Voltage Range: 2.5V to 3.3V.
- Wiring Resistance: Less than 5 ohms.
References
- REDI-Sensor. (n.d.). When One TPMS Sensor Fails. Retrieved from https://www.redi-sensor.com/when-one-tpms-sensor-fails/
- CarParts.com. (2024). What is a TPMS Sensor? Signs and Causes of Failure, and More. Retrieved from https://www.carparts.com/blog/what-is-a-tpms-sensor-signs-and-causes-of-failure-and-more/
- Mechanics Stack Exchange. (2016). Is it normal both TPMS sensors fail just after changing tires? Retrieved from https://mechanics.stackexchange.com/questions/24811/is-it-normal-both-tpms-sensors-fail-just-after-changing-tires
- Newparts.com. (2023). What Is a Tire Pressure Sensor and How to Troubleshoot It? Retrieved from https://newparts.com/articles/what-is-a-tire-pressure-sensor-and-how-to-troubleshoot-it/