Understanding your Tire Pressure Monitoring System (TPMS)
Question: My ‘low tire pressure’ light came last week. I added air and the light went off. Was that the right thing to do, or do I need to worry about a slow leak?
Answer: As you witnessed, the light was telling you the air pressure in one or more tires had dropped below a desired level.
This is an important warning from your Tire Pressure Monitoring System (TPMS) because underinflated tires reduce your MPG, wear your tread prematurely, and pose safety issues.
Sometimes the tires are low because of a slow leak, as you know, and sometimes the light is triggered by a significant, swift drop in temperature.
Yes, it can be a nuisance. But the fix is easy and costs next to nothing.
Here’s what’s happening:
- All 2008 and newer cars and trucks, as well as many 2006 and 2007 vehicles, are equipped with a TPMS, which turns on a dashboard warning light when the air in any of your tires drops about 25 percent beneath the recommended psi.
- For every 10 degrees the air temperature changes, your tire pressure can change about 1 psi. If you last checked your tires when it was 90 degrees and the overnight temps are now dipping into the 40s, your tire pressure could have dropped 4 to 5 psi.
- What to do? Check and adjust your tire pressure in the morning before you drive more than a few miles and before the daytime temperatures rise.
- In many vehicles, the tire pressure light will turn itself off once you add air. In others, you’ll need to reset the light. Consult your owner’s manual for instructions, or if you need help, stop by John’s Auto Service. We’re here for you!
If you add air more than twice and the light continues to come, bring your vehicle in and let us take a look at the tire. It’s possible there is a slow leak in the tread, a leak at the rim or some hard-to-see tire damage.