Had valve stem replaced on my Prius, now the TPMS light is on?

08 Toyota Prius

Long story short I brought all new tires. But one tire had a slow leak. I take it back and they say it’s the valve stem and they replaced it no charge.

I get in my car and the TPMS light is on, so I check the PSI it’s at 42 instead of its recommended 35. I deflated it and the light is still on… what’s going on here?

Most older Toyota’s have a tpms reset button under the steering wheel that relearns the sensors.

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@TXdealer Shouldn’t that not matter when they change the valve stem and not the sensor?

I don’t remember exactly the setup on your car. I would try the reset button and see if the light goes out. If not, they likely didn’t program the sensor correctly. On many cars, the valve stem is the sensor.

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How much to program a sensor? I’m almost positive Conrad’s didn’t do that

Discount tire charges around $60 a wheel for sensors and programming. Have you tried the reset procedure yet?2008 Prius TPMS Reset Button Location - YouTube

Check the pressure in all the tires.


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I haven’t. I’ll give it a shot. tomorrow. But I know all my tires are inflated correctly now

As above, resetting the TPMS is relatively simple. Just follow the procedure posted above.
However, if your car still has the original TPMS sensors, just coincidence one or more failed at this time.
Most TPMS sensors run on batteries that are built into the sensor and these batteries are not replaceable. The life expectancy of the lithium ion batteries in a TPMS sensor is anywhere from 5-10 years .

Try the resetting procedure first, if that does not work, likely need to replace sensors, do all four.

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When you start the car does the TPMS light flash for about a minute then turn solid? If so you have a dead or dying sensor battery in one or more tires. If your car can read individual pressures from the sensors (some can, some can’t) you can tell which one(s). If not a shop can. Don’t forget the spare some have sensors too.

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From what I can see online, the Prius, even in 2008, had a direct TPMS system. Look at your valve stems. If they are stiff metal, then they are direct TPMS. If they are flexible rubber stems, then you have indirect TPMS. Normally, the entire sensor needs to be replaced in a direct system as the valve is built into it. So it is kind of suspect they would just replace the valve or not charge if they replaced the sensor. I ran across a car once where the tire shop had replaced a direct TPMS sensor with a rubber stem and no sensor so double check. If they are all the same, then try the relearn procedure (although any decent tire store would not let you drive off without also doing it for you).

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The stem is metal where the cap screws on, but is very flimsy as a whole like cheap rubber. Does this mean they didn’t include the sensor? @TwinTurbo

Why are you not going to another tire shop that might solve this problem ?

@VOLVO-V70 I am but just making sure what it is before I go. Also the tire light does blink before going solid. So I bet there’s no sensor

The factory tire pressure sensor has a metal valve stem and has replacable seals. Some aftermarket tire pressure sensors have a rubber stem but some are not compatible with your vehicle’s receiver.

Since you were not charged for a new sensor, they might have installed a common rubber valve stem. Does your invoice advise that you have a new sensor installed at a dealer?

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@Nevada_545 they didn’t give me a receipt or anything. When usually Conrad’s does. Probably just a rubber stem huh?

I don’t know what Conrads is or how good their service is . But a real tire shop can tell you if the sensor is bad or just needs program . That is their job so let them solve this.

They tried to solve it 3 times already and failed. I’m not taking it to another shop until I know what the issue is.
It appears that it’s just a common valve stem so I’ll just have to purchase one and take it to a local mechanic to have it programmed

Do you have a spare tire? if so, check the tire pressure. your vehicle might read that one too. if it is low it will set off a warning.

No. Take your car to your local mechanic and tell them the symptom. Let them solve it for you, with them supplying the necessary parts. Otherwise you may end up stymied, the shop saying the part you supplied is faulty, and you saying their install is faulty.

No experience w/you car. Generally there’s two basic designs auto manufacturers use to monitor the tire pressures. The indirect method, the computer estimates the tire pressure by measuring the wheel speed. No actual pressure sensors involved. Uses the standard-been-around-for-ages rubber valve stems. The direct method, a pressure sensor located inside the tire (but part of the valve stem ass’y that also sticks outside the tire) using batteries, it transmits a signal, received by a computer in the car, telling the computer each of the tire pressures. On this type the spare tire often transmits the signal too, so if you have this type, make sure to check the pressure of the spare tire.