Low Tire Pressure light won't turn off


Hi All,

Have a 99 Pontiac Grand Am GT and the Low Tire Pressure light won’t turn off.

All 4 tires are properly inflated. They are 4 new tires, but same problem did occur with the older ones. Any suggestions on how to turn this warning light off?




Does your vehicle take its pressure readings from inside the tires, or does it use the ABS wheel speed sensors?

If the former perhaps one of the pressure sensors is bad, it it’s the latter a wheel speed sensor could be bad, but I think that would illuminate the ABS light as well.


First are the tires inflated to the proper level? The information for proper inflation can be found on a label affixed to the drivers door or the trunk lid or the owners manual. If the required pressure is different front to rear make sure that is the way you inflate the tires.
Second some GM vehicles have a pressure sensor mounted in the spare tire as well. This tire should be checked for proper inflation.
If all pressures are correct you need to pay a visit to your dealer. The tire pressure monitoring system can be scanned to locate which pressure sensor is bad. My first though was that a sensor was damaged do to improper mounting of the new tires (very common) but you say it was on with the old ones so that is probably not the case. Hope it helps.


Are they all the same size and type tyres?


You might want to try resetting the system as well. Here is some info I found about it.

Reset Check Tire Pressure Light
The tire inflation monitoring (TIM) system detects the differences in tire rotation speeds that are caused by changes in tire pressure. The TIM may not alert the driver if the pressure in more than one tire is high or low. The TIM also may not operate properly if the spare tire is in use.

The TIM system can alert the driver when a large change in the pressure of one tire exists. The system only detects a low pressure condition while the vehicle is being driven.

The CHECK TIRE PRESSURE (Pontiac) or LOW TIRE PRESSURE (Oldsmobile) indicator turns ON in the instrument cluster if the tire pressure in one tire becomes 12 psi (55 kPa) lower or higher than the other 3 tires and the ignition switch is in the ON position. The message does not appear if more than one tire is low or high, or if the system is not calibrated properly. The system does not inform the driver which tire is low. In order to clear this message, equalize the tire pressures in all 4 tires and perform the system Reset Procedure. In addition, the indicator may come ON if a low voltage condition is present.

Whenever a tire pressure is changed, (tire rotation, tire replacement, spare tire, etc.) perform the Reset Procedure. Whenever the battery is disconnected, perform the Reset Procedure.

Do not perform the RESET procedure without first correcting the cause of the malfunction and checking and adjusting the pressure in all 4 tires. If you press the button when the tire pressures are incorrect, the Tire Inflation Monitoring system will not work properly and may not alert the driver when a tire is low.

Set all tires to the manufacturer’s recommended pressure.

Turn the ignition switch to the ON position, engine OFF.

Press the RESET button and release. The CHANGE OIL indicator will start flashing.

Press and release the RESET button again. The CHANGE OIL indicator will turn OFF and the CHECK TIRE PRESSURE (Pontiac) or LOW TIRE PRESSURE (Oldsmobile) indicator will start flashing.

While the CHECK TIRE PRESSURE (Pontiac) or LOW TIRE PRESSURE (Oldsmobile) indicator is flashing, press and hold the RESET button until the chime sounds.

The system completes the procedure by going through a relearn process while the customer drives the vehicle.

It takes 15 to 20 minutes to learn tire pressures in each of 3 speed ranges (15-40 MPH, 40-65 MPH, above 65 MPH). After about 60 minutes of driving across all speed ranges, the system will alert the driver if a tire is 12 psi different from the other 3 tires for 2-8 minutes.

Detection thresholds may be higher and detection times may be longer on rough roads, curves and at high speeds. The system is not capable of detection at speeds greater than 75 MPH.


Does the spare have a sensor??? If so what’s it preasure??


Exactly right. My Sienna had that problem, and I learned the set up procedure is in the book. Sigh.

An acquaintance had been driving around for a year or two with that light on, because he didn’t know how to reset it. The reset procedure for Sienna is slightly different than you show for GM, but the idea is the same.