TPMS - one bad tire pressure monitor sensor - replace 1 or 4?

Its usually safe to assume that if 1 is going bad after 6 years of use, then the others are right behind.

I had my TPMS light go on just earlier this month with my snow tires on. Brought it into the tire shop, front right sensor is bad. They replaced it. Couldnt get the TPMS sensors to sync with the computer. The TPMS module did not like the 1 different sensor. I had to have all 4 replaced. Now the light is off, I have 4 new sensors with new batteries and life is good!

FWIW, the independent tire shop in my area charges $50 per tire per sensor installed and programmed. I would call and price around before committing to any one place. The prices vary shop to shop.

 

I'd live with it as is and then replace all four when you get new tires, assuming you have a tire guage.

 

A tireshop that sells and installs sensors should be able to program them for you, most likely for less money than a regular hybrid mechanic would charge. One stop shopping.

As Priusguy said, if one has gone bad, the others are probably not too far behind. The most common failure mode is the battery in the sensor wearing out.

 

Before I got my Prius, my Jeep had an issue...I blew a tire, replaced it and the sensor, and the sensor never worked right or synched w/the car. I didn't care as I knew I was trading it in for my Prius but, you may want to consider doing them all at once and save yourself the headache.

 

Care to share the statistical analysis that leads you to this conclusion?

What is the MTBF for a single sensor? I'd have thought it to be a lot longer than 6 years.

 

Yeah no problem. I dont have much time to do "statistical analysis" on TPMS sensors But its pretty much common knowledge that the sensors last 4-7 years on the Prius (6 years on them is pretty good as the batteries are really small). Its a very safe assumption using common sense that if 1 sensor failed after 6 years, the other sensors that have had the same service duty are right behind.

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Also the MTBF isnt linear. One can fail today after a 7 year (average) lifespan, and another in 1 day or 1 month or ... My experience is I had one fail (my Prius is an 07) and while the tire shop was programming the NEW TPMS sensor, another went bad during programming. They recommended (and I totally agreed!) replacing all 4 so I wouldnt have to keep replacing TPMS sensors ala carte and wasting my time going back to the tire shop.

 

You see, you're contradicting yourself.

Failures of independent systems do not correlate with each other... unless you set the car on fire, of course all should fail at the same time. There are no grounds to claim that one failure means another failure will occur with 100% certainty in a given time interval; this is not how statistics work.


It's totally OK to say "I don't know".

 

Oh of course I dont know when/if the sensors will fail - I didnt know with mine either. My Prius is an 07 like the OP's and I just had the same issue earlier this month. Its a crap shoot, really. But we do know the expected designed lifespan and what you can expect the average life to be. I think I made that clear. Its safe to say though, that if 1 sensor fails near/at the end of its expected lifespan, the others are going to be following soon. The batteries do not have infinite life!

I wouldnt apply so much engineering math and science to the OP's question, its one of those common sense things. If you buy 4 tires, they have at least an expected 60,000 mile life and 1 or more tires are balding/dry rotting at 59,999 miles, you can probably assume that the other tires are coming up on their replacement soon - its also prudent to replace all 4 tires as a set, just like the TPMS sensors nearing the end of their battery life. In contrast, a TPMS sensor that has lasted 6 years of an average 7 year life span like the OP's....

Of course, there are people who let the sensors fail and put tape over the light. YMMV.

 

I'd be inclined to just let them die, ignore the warning light. By far the cheapest option

 

How much is it to have the sensors changed?

 

I just had all four tires and sensor batteries replaced but the light still won't go off, any advice? Tires programmed and tried reset already.

 

I'm not sure, but I think it's not possible to replace the batteries on the sensors. Maybe the whole sensor was replaced, and something is screwed up regarding initializing them?

 

I had an interesting experience at the tire shop when I owned my 2007... they replaced all 4 sensors but put the wrong ones in!
The ones they had installed didnt communicate at the right ghz than what was required. The TPMS telltale on the dash would not extinguish no matter what the tire shop or I tried.

They finally replaced all 4 sensors "again" and the light went off and stayed off. Of course, there was no additional cost to me as it was their mistake, but it was a learning lesson for their shop.

 

A piece of black electrical tape placed artfully makes the shiny light on the dash disappear, the alloy wheels of my '06 are melting, the sensors already melted.

 

Just got my prius 2008.
I never heard of tyre sensors. What do they do and how do I know if mine are working?

 

I think they're more trouble and more expensive than they are worth. I check the air in my tires at least once a month anyway. I don't intend to replace them when they fail and I think the tape over the light is a good idea.

 

A few years ago, I would totally agree with you. HOWEVER, twice now the system has functioned as designed and notified me of a low air pressure condition while I was driving. I too check my tire pressures frequently (mostly for mpg reasons) and I would not have caught it as I checked the tire pressure the week before. One time I was on the highway - I picked up a piece of metal in the tire and the tire was losing pressure slowly. It afforded me the opportunity to get off at the exit and change the tire.

And the system does function properly 95% of the time. Don't let the very few times it malfunctions discourage you from benefiting from the real safety benefit of the system...