Wednesday, December 24, 2014

Technolousy...

So, the Mrs.' car has one of those "tire pressure indicator" lights on the dashboard. You know what I'm talking about: a warning light goes on when one of the tires is a certain percentage below the recommended air pressure. Her car even has a helpful schematic that shows which tire is responsible.

Sounds great, doesn't it? I know one of my biggest worries with the truck stems from tire pressure. Now, granted, that comes from having run over a large spike, blowing one of the rear tires, and having to deal with a 3-ton pickup truck with only three points of contact with the ground instead of four (yes, I know the blown tire was still contacting the ground, but you know what I mean).

Except that the sensor has been right twice, and wrong about 180 other times.

It kicks on when the temperature changes. It kicks on when it rains. It kicks on when a butterfly flaps its wings too fast in the Andes. It's on a lot. When we first got the car, the light coming on was cause for much consternation. "Check the tire pressure, quick!" we'd yell, as these are moderately pricey tires (and there may have been an incident involving a car that needed an alignment and four new Pirelli tires, two of which were ruined inside of a month that I may or may not have reminded the Mrs. of once or a dozen times...)

So, now, we ignore the light. Sure, I'll glance at the alleged offender when I get out of the car, see that it doesn't look low. I might even hook it up to the (free) air station at the local gas station to find out that the tire is perfectly fine. More or less, though, we don't pay the light any attention whatsoever.

Basically, that warning light is useless. It has been used so many times, and been wrong so many times, that the one or two times that a tire has actually been low (and not dangerously low either time, once it was 10 PSI low, the other in the single digits) it's been right only through attrition. Imagine that: cry wolf enough times, and the warning starts going unheeded.

It's almost like something else I keep hearing, but just can't put my finger on...

That is all.


- Posted using BlogPress from my iPad

18 comments:

Ted said...

That's strange. The tire pressure indicator in my German made SUV techno - marvel has been triggered only once ( correctly ). But I still don't trust it so I still check the pressures manually more or less monthly.

Paul, Dammit! said...

I've got an oxygen sensor that kicks off the idiot light in my wife's car... 3 times it's shut itself off when I got in the car to bring it to the dealership.

Roy said...

Those tire pressure warning lights are just one more annoyance that has been mandated by the government safety Nazi's. I hate those things. And because they're now mandated, the auto manufacturers do them on the cheap, and of course, you get what you pay for.

The one on my Dodge Caravan used to constantly go off. And when I would check the pressures, the offending tire has been as little as 3 pounds low.

The light really is an annoyance, especially at night, so what I have started doing is I routinely pressurize the tires about 5 pounds above spec. That's not a 100% fix, but after I started doing that, my tire indicator doesn't light up near as often and then only if a tire is really low.

Roy said...

Paul, those Oxygen sensors actually have a shelf life and they are a common cause of the "Check Engine" light. If you're sure it's the O2 sensor that's causing the sporadic light, I would just go ahead and either replace it myself or have it done.

Stretch said...

My mother-in-law's Impala has those damn things. It's gotten to the point when the Smarter Half and I arrive in FLA I check the Impala tires, inflate if needed, and ignore the sensors the rest of the visit. An yes, they will go on when I hit wet pavement, drive more than 10 miles, or even when going up a hill/ramp.

ASM826 said...

So, when are cars going to be "smart enough" to provide the driver with an interface? You know, like a tablet computer interface to the electronics.

Let the owner see what is setting off the big orange CHECK ENGINE light and turn off the bulb if it's minor so it's not a big glowing distraction to night time driving.

Let me set the range of tire pressures that will trip a warning, and see what pressure it's actually at when it throws a warning.

Let me customize some of the screens like I actually own the vehicle.

It's past time. Someone is going to do this and then everyone will have to follow along.

Anonymous said...

OK, so the TPMS system has some definate issues.

1) The TPMS is triggered when a tire is 10% under inflated. (For my tires at 35 PSI, that is a drop to 31.5 PSI.)
2) Sometimes, the sender/reader needs a battery replaced (a tire becomes antisocial)
3) Conditions (temp change/wet) will cause an air pressure to fluctuate about 1-2 PSI (which means if it is normally 35 but has bled off to 33, it will trigger).
4) Like commercial airline pilots, we get used to the warning lights and tend to start ignoring them. (Boy who cried wolf, anyone?)

Overall, I find them interesting, yet useless.

Joseph in IL

Sdv1949 said...

...and the tire pressure have an approximately 5-7 year life expectancy. Put in a new one.

Kermit said...

Or you know, just do what people did for decades prior to the TPMS' introduction...

Walk around the car, kick each tire, and if you're feeling fancy, use a handheld pressure gauge.

The stupid little "flat light" can be covered up with a piece of electrical tape... ::coughcoughahem::

Oh, as an aside, if you have to change a flat, the TPMS must be reset. If you take a tire/rim off and put it back on, the TPMS must be reset. If you patch a flat before going in to the tire shop, tht TPMS needs to be reset. Oftentimes, if the tire gets low enough, the TPMS must be reset after reinflation, even if the tire and rim never left the wheel. And the only folks that have the tool to reset it are usually the dealerships and mechanic shops...

Old NFO said...

Kermit is right... sigh... Merry Christmas to you and yours!!!

Brad_in_MA said...

My wife's Honda has one of those fancy sensor things. It mostly works but does get weird in cold weather.

Her car used to have run flat tires. Used to. Never again. NEVER.

Glenn B said...

Screw all this unreliable technology, give me a horse and I would be happy (although I am sure my lard butt would hurt). With a horse, I know it would be as good as I treat it and if it went lame I could shoot it and eat it. Try that with a Buick.

bogie said...

My sensor is always right and it has saved me on many an occasion from slow leaks caused by nails. Also, when cold weather hits, pressure goes down, so I correct it.

It also lets me know when I take it to a shop and the technician is too lazy to look up specs (on the door of the vehicle) and lets out air so they are all at 32. I turn the key, the low pressure light goes on and I walk right back into the shop to have them fill them up to 35. I've also had techs try to fool me by putting that they inflated the tires to 35 on the paperwork, but look, they let air out an they are at 32.

Not once have I gotten a false warning.

Jay G said...

As it turns out, this time it was correct. Checked the pressure and the tire was down 4 PSI. Filled it up and the light was off the entire trip home.

D'OH!

Bradley said...

does it tell you what tire to look at? in my Mustang GT, it does not, in my buddies GT500 it does, and in my friends Chevy TrailBlazer SS not only does it tell you what tire, it shows the pressure in all the tires at one of the info screens.

Will said...

Most people try to judge the pressure in a radial tire by looking directly at the sidewall of the tire. You can NOT do this reliably. This only works with the old bias ply tires.

If you don't have a gauge, stand back about the distance you would be when stopped in traffic, and compare both tires. If one is bulged more than the other, it is probably low, unless you are carrying an offset load.
(if you can't see both rear tires road contact point of the vehicle in front of you when stopped, you are doing it wrong. This distance allows you to go around them without backing up, if you need to get down the road. It's a security, and collision, concern)

Anonymous said...

My Hyundai POV has the "tire pressure low" warning, and on one occasion it was wrong, and on four occasions I had a nail in a tire. It will go on momentarily when it gets real cold (well below zero), but turns off in a couple miles.

My work truck tells you WHICH tire is low. Until you rotate the tires. Then it doesn't reset itself, which can be really annoying. And when you DO get a flat, and put the flat tire in the back of the truck and drive home, it keeps telling you that the tire lying in your bed is at low pressure, do something!

My boss's work rig is a 14 Grand Cherokee. It tells you the actual PSI in each tire on a dash screen you can cycle to and through. If one tire gets down to 29 PSI or lower, it lights up the dash light. It is sensitive enough that in cold weather, the sun shining on one side of the truck can make enough difference to set it off. Annoying as hell. And just TRY to get all 4 tires to the same pressure outside in the parking lot.

Tony Tsquared said...

I have them on my wife's Mini, my Ford Fusion, and my daughter's Volvo C30. The Mini will tell me which tire when it drops 5 psi below the "set" pressure. It has been right twice with no false alarms.

The Ford will tell me I have a tire low. It will not tell me which one and it will go off with a deviance of 3 % plus or minus. In the summer in south Georgia if you park with the tires against a curb the added pressure of the tire against the curb and the warm ambient temp will set it off. If the outside temp is 102+ degrees and you pull into a parking lot that has black asphalt and stop for 10 minutes it will go off. You get to where you ignore it as it it always coming on and when you do have an actual low tire and you have ignored the tire pressure light so much you will have a blow-out (I have done this twice). It has a 98% wrong average with a 2% right that has cost me 2 new tires. I wish this car didn't have the feature as I have gotten into the habit of checking the tire pressure every week on this car.

The Volvo C30 has never had the light on until it received new tires about 6 months ago. It was recalibrated and has never come back on.