Mechanics

Low Tire Indicator Warning Light

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Step by step guide on how an automotive tire pressure indicator system works, this information pertains to most systems.

Step 1 - Sensors are used to monitor individual tire pressure in all tires including the spare. If air pressure in any given tire goes below or above minimum or maximum requirements the warning light will illuminate.

Step 2 - Each sensor gives feedback data, which is then transmitted to the central controller where calculations are performed.

Helpful Information

The LTI (low tire indicator) was devised to help prevent accidents due to low tire pressure. A receiver picks up the signal from the tire transponder and then sends the information across an information bus. These processors then compute information and send a signal to an onboard diagnostic center which includes a warning light located on the dash. Some vehicles include integrated remote service like OnStar, that can send a message to a phone when the low tire inductor warning system has been activated.


Low Tire Lamp Inductor

If the air pressure in all tires is correct including the spare tire and the indicator is still on, a tire sensor has probably failed, or the system requires a reset procedure.

Preferred Procedure

It is best to check air pressures after the car has been standing for a few hours on cool pavement. To locate the air pressure specification consult the driver's door jamb sticker, or consult the owners manual.

Common Problems

  • When replacing a tire or normal tire services (flat tire) the air pressure sensor can be damaged.
  • Air pressure gauge can be off (not within calibration specifications.)
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AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2014-07-11)