Dreaded tire pressure light.

You need to check the tires and add air where needed. That is what the TPMS light is telling you. After that the light may take a couple of minutes to turn off.

 

TPMS sensor batteries are starting to fail. BTDT They're good for about 10 years give or take.

 

Possible too. Since they mentioned a tire was low but did not say they added air, I thought that bore mentioning too.

 

Depending on what State you're in, you may or may not need to pass an annual inspection where a tpms light will mean a fail. That's one hurdle. The second: I believe in the States all tire shops are under the gun to install tires with functioning tpms?

 

There is a TPMS reset button under the steering wheel?

 

There is usually some way to set the TPMS when you are sure all tire pressures are correct. It is not a reset button.

 

When you say one was low 5 psi, based on what, the door sticker? If so, that makes sense because most Toyota models hold to a 15% pressure loss to set the TPMS light and it just so happens that 5 psi is almost exactly a 15% loss on 33/35psi > the pressure Toyota specs for these cars.

Now, if you have modern higher pressure LRR tires, 28 odd psi is a WAY UNSAFELY LOW pressure. The "rule of thumb" in the tire industry (tire manufacturers that is) is that no tire should ever be inflated to LESS than 75% of the sidewall "MAX COLD", but in certain cases with lightly loaded tires pressure lower than that can be approved by the tire manufacturer, especially if speeds are low.

 

Permanently installed in the sensors, ie: not replaceable.

 

Registering the sensors is easy if you've got access to Techstream. But yeah, you do have to buy them....

-Chap

 

Search the Prius Chat forums and internet for how to use a mini VCI cable, techstream, etc. You'll find the answers.

 

You can see this for DIY assist
TPMS Management with Techstream | PriusChat

Sounds like one TPMS went bad...I lost one so far at 165k miles (the dead one lasted 9.5 years at 150k)...cheapest quote I got from my tire place was $30 to replace if I supply the TPMS and program. I know from Techstream where the bad one is.

 

I agree with everyone else, TPMS battery went bad. Check your local mom & pop tire shops, they can replace and reprogram them. I had to do one on mine the day I bought it and it was cheaper than $150 (not sure what prices are like in your area). Even if you get tech stream, you still have to get the sensor installed inside the tires. My local shop price included the part, install and reprogram.

 

Cheapest option with the TPMS is to just keep driving, checking your tire pressures regularly until your current set of tires wear out. Then buy and bring a new set of TPMS sensors with you when you get the tires replaced and most tire shops will install them for free with your new tires. I probably wouldn't replace just a single sensor unless I needed to, to pass an inspection.

 

As a way to spread the word to each GEN that qualifies, see this new thread on Individual tire TPMS with a ScanGauge II.

Attn: ScanGauge II Owners! Individual tire TPMS data! | PriusChat