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Friday, November 13, 2020

The brightly shining warning light

© Mark Ollig


After starting my car recently, I was surprised by the sudden appearance of an illuminated yellow alert indicator above the speedometer gauge.

I stared at this unfamiliar symbol, wondering what it meant.

“It’s yellow, not red so it can’t be a critical alert condition,” I thought while remembering an episode of Star Trek with the flashing “Red Alert” symbol filling the television screen.

A bright yellow exclamation point was in the middle of what looked like two slightly swelled, yellow parentheses connected to a flat, linear baseline. This baseline had four black parallel rectangular squares etched half-way through.

“Could this symbol mean I need more oil?” I wondered.

I opened the glove compartment, found, and briefly flipped through the bulky car owner’s manual that may have equaled the page count of “War and Peace.”

Becoming somewhat impatient, I decided to call the dealership where I purchased the car.

Speaking with the service department, I described this mysterious yellow icon symbol and asked if I could stop in to have them look at it.

“No problem, someone will help you when you arrive,” they confidently reassured me.

I can hear some of my readers chuckling out there – you know what this yellow icon symbol means, don’t you?

Remember, folks; this is my first new car of the 21st century.

I had been previously driving a 1999 Ford Crown Victoria Police Interceptor with the powerful V8 engine, and, as Elwood in the “Blues Brothers” movie said, “it’s got cop tires, cop suspensions, and cop shocks.”

The Interceptor used analog gauges and icons, which, when illuminated, had a name associated with them, not symbols requiring a degree in deciphering automotive hieroglyphs.

Driving my car into the dealership, I steered towards the service garage.

As I approached the service bay door, it suddenly opened, and a smiling service person inside appeared and waved me in.

“So, let’s take a look,” he said while checking the instrumentation cluster panel with the yellow symbol still brightly shining.

“You have low air pressure on one of your tires,” he knowledgeably said to me.

“Ah. So, that’s what it is,” I sheepishly said.

It seems the yellow icon I saw symbolized the cross-section of an under-inflated tire; the exclamation point emphasized the low tire pressure.

My car model has an air-pressure monitoring sensor in all four tires, but determining which tire has the low pressure requires measuring each tire’s air pressure individually.

Some car models have an icon symbol displaying all four tires with their current air pressure reading.

The next car I own will definitely have this.

After the service attendant measured the air in all four tires, he discovered the front-right tire with the low air pressure.

This tire was taken off and inspected; a nail caused the air leak. I had the tire patched.

The yellow low tire air pressure symbol is called the TPMS (Tire Pressure Monitoring System) alert indicator.

A TPMS sensor is mounted inside each tire rim and includes a battery.

Upon reaching a tire’s low air pressure setting, a sensor activates the yellow dashboard TPMS symbol light, using a low-frequency radio signal.

The TPMS battery is encased inside each tire pressure sensor device and has a life expectancy of approximately five years.

When this battery becomes low, the yellow tire pressure indicator symbol will flash, and the dealership will replace the entire sensor unit and reset its threshold settings.

I assume when one TPMS battery sensor is low, the other three probably are too and would be replaced.

The TPMS alert, no doubt, saved me from ending up with a flat tire, or worse, a tire blow out while driving.

So, I am therefore thankful for having the TPMS installed.

Correct tire pressure improves fuel economy, lengthens a tire’s road life, and, most importantly, increases safety by avoiding accidents caused by under-inflated tires.

The National Highway Traffic Safety Administration enacted a TPMS mandatory compliance date for all new light-motor vehicles sold after Sept. 1, 2007.

The Reader’s Digest has an informative article showing and explaining many of our car’s dashboard symbols at https://bit.ly/3n6lSsv.

Incidentally, after I returned from the dealership, I found the tire low-pressure warning icon symbol and its description on page four of my car owner’s “Quick Start Guide.”

Stay safe out there.

TPMS (Tire Pressure Monitoring System) alert indicator