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TPMS Questions

Discussion in 'Gen 2 Prius Technical Discussion' started by snijd, Dec 15, 2009.

  1. snijd

    snijd DIY or die

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    Last fall, I installed snow tires with steel wheels on my '06 Prius. They had no TPMS installed. As expected, the tire pressure icon lit up shortly after this, and stayed on--for several weeks. Then it went out, and stayed out. Is this a failure of the TPMS ECU? Might the fix described in TSB-0084-09 (TPMS Tire Registration "Lost Communication With ECU") resolve this?

    If it does, then I'm wondering about entry of the sensor codes. Can Techstream discover the codes, or must the technician already know them, by physical inspection? Based on the instructions in this TSB, it appears that previous knowledge of the codes is needed.

    Anyone know the answers?
     
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  2. RobH

    RobH Senior Member

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    There are mechanic's tools that read sensor ids from each tire, and then send them back in via the OBD port. Techstream requires that you already have the ids.

    Edit: Here's a link to some dealer TPMS tools: TPMS Dealer Tool & TPMS Dealer Tools from Bartec USA
     
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  3. snijd

    snijd DIY or die

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    Maybe I can find a service center with such a tool, but the Toyota dealer says they normally dismount the tire to inspect the sensor. The service advisor also told me that if the car doesn't see the sensors for long enough, it will simply forget the IDs. I'd never heard this before, but it explains my car's behavior.
     
  4. alanh

    alanh Active Member

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    I'd think it would still complain if it didn't see 4 sensors all the time. Do you park near where the summer rims are stored?
     
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  5. triumph1

    triumph1 Member

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    That's what I was thinking- If you park in front of the garage or wherever the tires are stored, and don't travel further than 55 minutes away, they supposedly won't light up.
     
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  6. snijd

    snijd DIY or die

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    Interesting. I tested the system by reducing pressure in one tire, and the light came on. So, it still works. Hadn't heard about the "55 minute rule." The summer tires were stored several yards from the car.
     
  7. PRIUS007

    PRIUS007 James Bond -007

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    I don't think it's going to make any difference if the vehicle is parked next to the 'Summer' tires. The TPMS activates via the rolling of the tires in order to 'energize' them to send the signal to the computer. If they did not work like this, you'd be having to replace batteries in the TPMS sensors all the time.
     
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  8. alanh

    alanh Active Member

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    As far as I know, the TPMS sensors have long-life lithium batteries, with an estimated life of around 10 years. They do not recharge from rolling. At the 10 year mark, yes, you'll have to replace them.
     
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  9. Judgeless

    Judgeless Senior Member

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    The TPMS sensors do not charge as the car moves. They have a 10 year battery as posted here.

    I have my original rims, sensors and tires in the garage. When I start the car it communicates with the tires in the garage and the TPMS light stays off. It takes about 15 minutes to make the TPMS light start blinking after I leave the garage.
     
  10. vertex

    vertex Active Member

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    [FONT=&quot]Here is a look at the inside of the TPMS:
    [/FONT] [FONT=&quot][​IMG]
    [/FONT]
     
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  11. N3FOL

    N3FOL Member

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    Re: TPMS Lit On and Off (Sometimes)

    I have a different situation...2 days ago my TPMS warning light lit up on the dash and I figured I may be low on air. The following day, I checked all tires and the front read 35 psi and the rear at 34 psi. I normally put 40 for the front and 38 for the rear. So that is what is did...pumped the tires up to my usual 40 - 38 psi. (had to add air on all 4 tires) Driving down the road, the warning light stayed lit for about 10 minutes and then went out for the rest of the ride. Tonight, I went to watch a movie...after 10 minutes of driving, my TPMS warning light lit up again.

    Not sure if I am loosing air or not. I feel like the warning light is intermittent. Is there something going bad here....fyi, all my tires are OEM. No modifications. Any suggestions?
     
  12. Bob64

    Bob64 Sapphire of the Blue Sky

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    Try to recalibrate your TPMS after you re-inflate em. Once calibrated, it'll warn you after the pressure drops 25%.

    I'd also doublecheck the pressures. A nail in the tire may leak air only while moving or only leak air to a certain psi...
     
  13. N3FOL

    N3FOL Member

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    So far so good on my psi. Front and Rear Tire pressures are holding. Later today I will have to double check the pressure and see if it dropped or not. fyi, this only started to happen after I washed the car and sprayed the tires near subfreezing temps.
     
  14. GreenClipper

    GreenClipper Senior Member

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    Had an "Owners Appreciation" dinner last week and one thing I learned from the Service Mgr. at the dealership, which I have not seen info on here in the forum. Service Mgr. stated: Do not use metal caps on the tpms. They will corrode and will not be able to be removed w/o force which will break the tpms. (Meaning; Expensive repair)! So if you like the "chrome" look, down to the tire valve caps, I guess you need to paint the rubber/plastic ones with a chrome paint.
     
  15. N3FOL

    N3FOL Member

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    Update on my TPMS

    My tire pressure is staying steady, but my TPMS warning light blinks for awhile and then stays solid. This has been going on for a month now.

    Saturday morning, I have an appointment with the dealership. This should be diagnosed and repaired under warranty. The dealer said it should take about an hour for them to take a look. I'm crossing my fingers and hope that the dealer does not give me bad news. I'll let forum members know what Toyota finds out about my TPMS.