Low tire pressure light

I have a 2003 Impala which up until this past monday had a tire with a slow leak in it. On monday I had that leak repaired, well the shop said it was repaird. Then driving home last night I got the “low tire pressure light” coming on, and well figured they actually had NOT fixed the leak or I had a new one. I pulled off at a station to refill, but first checked all four tires, all four were exactly the same at 35 PSI, which is where they are suppsed to be. So my question, what could have set off the LTPL if none of the tires were low in pressure or no tire was significantly different from the others presure wise?

You need to reset the TPMS system. Follow the procedures below.

  1. Turn the ignition to ACC or ON and turn the
    radio off.
  2. Press and hold the TUNE DISP button on the radio for
    at least five seconds until SETTINGS is displayed.
  3. Press the SEEK PTYPE up or down arrow to scroll
    through the main menu.
  4. Scroll until TIRE MON appears on the display.
  5. Press the 1 PREV or 2 NEXT button to enter the
    submenu. RESET will be displayed.
  6. Press the TUNE DISP button to reset. A chime will
    be heard to verify the new setting and DONE will be
    displayed for one second.
  7. Once the monitor has been reset, scroll until EXIT
    appears on the display.
  8. Press the DISP button to exit programming. A chime
    will be heard to verify exit.
    The system completes the calibration process
    during driving.
    The system normally takes 15 to 20 minutes of driving
    in each of three speed ranges to “learn” tire pressures.
    The speed ranges are 15 to 40 mph (25 to 65 km/h),
    40 to 65 mph (65 to 105 km/h) and above 65 mph
    (105 km/h). When learning is complete, the system
    will alert you after two to eight minutes if a tire is 12 psi
    (83 kPa) different from the other three tires. 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
    70 mph (110 km/h).

Try this procedure to reset the system:

Your Impala uses speed sensors to detect differences in wheel speed. If one of the speed sensors is malfunctioning or one of the tire diameters is significantly different, the system will think a tire is underinflated.

Try resetting the system first as described in the link above.

Did you check your spare?

I have reset it so often I have it down pat, it was that reseting process that I learned how to shut off the security system so my car would restart. That is why I am baffled as to why it came on this time.

You may have a bad sensor on one of your wheels. BTW…they are usually not cheap so make sure it’s bad before you have it replaced. Here is another reset option using a scan tool:


This wasn’t your question, but I’ll point out that if your tires were at the recommended pressure after driving for a while in afternoon temperatures, then your tires are actually underinflated. They should be at the recommended pressure at the coldest part of the day before you drive on them.

I’m with JESMED on this one. 2003 didn’t have TPMS sensors, but used the ABS to alert driver to a sudden loss of tire pressure, so maybe look into the ABS, like maybe a wheel speed sensor failing intermittently.

First off, if the reset procedures don’t work, check the electrical connection at the wheel speed sensor on that wheel. Maybe it is knocked loose in the process of changing the tire. If that looks ok, not corroded, check the other three wheels.

All they did was fix the leak right? Not replace the tire. And they didn’t rotate the tires, right?

What that light means – when the system is calibrated and working correctly – is that the computer is detecting that one of the wheels is consistently rotating at a higher rpm than the other three. And it presumes the reason is the tire pressure is low, which makes the tire smaller, so it rotates faster.

But if you have any tires that are more worn than the others, or smaller for any other reason, like maybe a defective tire, that could cause it to light up too. I guess at last resort you could use one of those flexible cloth tape measures like used for fitting clothing and measure the circumference of the wheels, see if one is different than the others.

Edit: Above presume the info above is correct, this vehicle doesn’t use in-tire pressure sensors. Before embarking on a wild goose chase, might be a good idea to verify. B/c it is a pretty common thing to accidentally damage an in-tire pressure sensor while removing or installing the tire on the wheel.