tire low pressure light is always on

The TPMS system expects hear from all four registered ID codes within a particular time. I don't know the usual transmit interval (once or a few times per minute?), but if any sensor isn't heard from for a too-long time (10-15 minutes?), then the warning is set. At least, when I change seasonal wheel sets and forget to reprogram the car to recognized that set's codes, that is about how long I can drive before the alert turns on.

 

I thought we covered this already.
If money is REALLY tight, then sure just change out the one(s) that have actually failed.

But if I were doing it and I intended to keep the car for a while longer, I would just have them all done.
At 11 years old, the rest of them likely won't last long.

 

As alluded to by @bisco and others, you can just do nothing. Do keep on top of monitoring tire pressures; life goes on.

 

Yes, but it will act different than if there is a low pressure warning. I think it will blink first then stay solid. (Also color may be different, sorry not sure on that one).

 

Or just get one of these or these .......your wife can change all four batteries while you're watching the football game! ......

 

I was reading that thinking you were going to suggest these or these ....... honey, could you go change those TPMS sensors? I would, but the game's on.

 

Driving with non-tpms equipped snows through winter, I notice that “start with blinking, then progress to steady on” light. The wheels with (functioning) sensors are in the garage, right next to where the car is parked, so I think the car “catches up” with them, every time we get home.

Then when we drive off, it just holds its peace for a while, then finally starts the blinking. Like it’s saying “you know, I’ve looked everywhere, but can’t find those sensors”.

 

OMG, Mr. ByTheBook is cutting corners!

 

That's exactly what my iQ was doing. But at first driving along the freeway and missing the blinking part I thought I had a flat. Checking tire pressures I found them perfectly fine. Eventually I checked with the Autel tool and it could not read one of them, as in no response at all. Check out the Dorman units. They have one that is preprogrammed and one that is programmable. I'm interested to see how they will respond to a dead battery. As I know the TPMS sensors fall under their lifetime warranty category...

 

Whatever you decide to do, don't take back to a dealer to install TPMS sensors. They will rob you for the service that can be done at any local tire shop for a fraction of the cost. If you insist on using OEM TPMS sensors, it will cost more, but if you use aftermarket TPMS sensors, the cost will be $30-$50/tire. It is best to do this when you also have to change or buy a new set of tires. If I were you, just drive as is until you have to buy a new set of tires. And at that time let the tire shop take care of it.

 

I think he is still going by the book, but the Canadian book instead of the U.S. book.

 

There is only the one light to indicate either: a low pressure condition (the light just comes on steady); or a system fault (usually a dead or missing sensor- light blinks a bit then stays on).
Most repair shops have a tool that will wirelessly "ping" the sensors to see if they will respond- if it can respond it will send data (such as a unique ID, pressure temperature, and sometimes battery status - ok or low).
That said the typical lifespan for a sensor battery is about 10 years. So if they are all original then they could go anytime.

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I dont think the tire sensor is duplex, I believe it pings the vehicle about every 10s or so.

 

It sure seems that my RF reader has some way to trigger the TPMS sensor to transmit a prompt data packet. I do have to press the reader against the tire sidewall at the valve, and press a button, to trigger this action.

One website says:
"The majority of TPMS sensors are activated with a low frequency (LF) signal (125 KHz). This LF signal varies from vehicle to vehicle (some require more power than others) and forces the sensor to transmit. The TPMS sensors then transmit information and communicate via a UHF signal (314.9-433.92 MHz)."

 

Dealer wanted $100 per wheel. Discount tire quoted me $60 each.

 

Most TPMS sensors have an accelerometer built in. AFAIK if it doesn't detect rotational movement it will go into a sleep mode, and transmit maybe once every 5 minutes. Once the tire spins above 10-20 mph, it will start transmitting once or twice a minute. If it detects a rapid pressure drop it will transmit immediately.

Posted via the PriusChat mobile app.

 

Class A truck drivers are expected to do a walk around and visually inspect their vehicle at the beginning of every shift (it's on their checklist). It wouldn't kill the rest of us to spend 15 seconds doing the same.

 

You can still collect a nail enroute, but yeah: good practice.