Low Tire Indicator Warning Light

The LTI (low tire indicator) was devised to help prevent accidents due to low tire pressure. This system is beneficial for anyone that would like to know the air pressure of the car tires as they drive.  It also can alert you to a puncher in the tire that is allowing air to escape. The LTI warning lights are a featured safety device that is included on some cars. This air pressure monitoring system is used to use feedback data created by the transponders inside each tire. A receiver picks up the signal from the tire transponder and then sends the information across an information bus which is connected to various processors. These processors then compute information and then 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 you a message on your phone that a low tire inductor has been activated.

Low Tire Lamp Inductor
Low Tire Lamp Inductor

When a low tire indicator light illuminates all tires air pressures should be checked, including the spare tire. If you have inspected the air pressure in all tires including the spare tire and the indicator is still on this usually means one of two things. Either a sensor in one of the tires has gone bad or the system requires a reset procedure. If these actions still do not solve the problem you will need to determine what your particular problem is. Diagnostic procedure information is determined by the car manufacturer and a service repair manual is needed to obtain the manufacturer specific information. If all tires including the spare tire pressure in within specifications and the LTI light is still illuminated one of the feedback sensors in one of the tires has probably failed.

Preferred Procedure: It is best to check car tire air pressures after the car has been standing for a few hours on cool pavement. The reason for this is the air pressure in tires goes up slightly as you drive. This air expansion is a normal occurrence created by natural fiction generated by rolling resistance. To find the air pressure for your vehicle consult the driver's door jamb sticker or find air pressure specifications by consulting a car repair manual.

Common Problems

  • When replacing a tire or normal tire services (flat tire) the air pressure sensor can become damaged
  • Air pressure gauge can be off (not within calibration specifications)
If further assistance is needed, our certified car repair technicians are ready to answer your car questions.

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


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Article first published (Updated 2013-08-16)