The case of the ‘horseshoe’ dash symbol

  • James Halderman
12:00 a.m. Friday, Nov. 24, 2017 Cars
This typical dash warning symbol indicates the tire pressure monitoring system has detected a tire that has low inflation pressure. James Halderman photo

Wheels:

Mike M. from Centerville asks: “This fall, when it got cold, an orange or amber warning light came on that looks like a horseshoe. After driving the car for a few miles, the light went out and stayed out for the rest of the day. I have had warning lights come on before but nothing that looks like a horseshoe. I tried to tighten my gas cap and that has worked for me in the past. However, the next morning the horseshoe light came on again. What do you think this is and what is wrong with my car?”

Halderman: The horseshoe-shaped dash warning light represents a tire and the warning light is used to notify the driver of a tire that has low inflation pressure. All passenger vehicles since 2007 have been equipped with a tire pressure monitoring system that will light a dash light to warn the driver of a tire that has lost inflation pressure by 25 percent of the recommended pressure, as stated on the driver’s door placard. What likely happened was that when the temperature dropped, the pressure inside the tire decreased because the temperature and pressure are related. A drop in temperature of 10 degrees will cause the tire pressure to drop 1 PSI.

Therefore, check the inflation pressure of all tires, including the spare. Please note: Many SUVs use a tire pressure sensor in the spare as well as in each of the four tires on the ground. If one tire continues to lose inflation pressure, ask a professional service technician to find the root cause and correct it to keep the light out.

For a free chart that can be downloaded showing all the dash warning symbols with their meaning, visit www.jamesahalderman.com.

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