Tire pressure monitors

How this technology works

Tire pressure monitors check the air pressure of all the wheels and alert the driver when a tire's pressure has dropped below a safe level.

Two types of systems are currently in use:

  • One uses ABS sensors to measure the rotational speeds of the wheels. An under-inflated tire will have a slightly higher rotational speed
  • The second directly measures the pressure with a wheel mounted pressure sensor in each wheel


The system is on when the engine is turned on.


A dashboard display shows the level of pressure in each of a car’s tires. The back left tire pressure is too low, prompting an alert.

Things for drivers to keep in mind

  • Make sure you understand the tire pressure monitoring system installed in your vehicle
  • Some tire pressure monitoring systems provide a warning only when a tire is significantly underinflated. The tire may then be close to failure
  • When a monitoring system warns that pressure is low, measure your tire pressure and inflate to the appropriate pressure
  • Large temperature changes outside can cause the low tire pressure warning to come on
  • A warning message that the system is malfunctioning will also come on if the tires are changed or the tires are rotated and the system is not reset
  • When installing winter tires, be aware that the system may not work properly unless the correct type of pressure sensors for your vehicle are also installed
  • If buying new rims, make sure the pressure sensors fit on the rims
  • Newer tire pressure monitoring systems allow the driver to reset them
  • Tire pressure monitoring systems do not replace the maintenance procedures recommended in the owner's manual
  • You should continue to measure your tire pressure on a monthly basis
  • You should read your owner's manual to learn about your vehicle's system, including its capabilities and limits

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