exhaust temps, 1375f+ too hot?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by viciousthinker, May 13, 2025.

  1. viciousthinker

    viciousthinker Junior Member

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    hi all… can anyone clarify or define what a normal range of exhaust temps on our third-gens would be? for reference i’m in houston, and the temps i was looking at were while driving at 50-60mph and during 70f weather… i am deriving my temps from readings of the sensors labeled

    catalyst temperature sensor 1 b1
    catalyst temperature sensor 1 b2

    i am regularly seeing temps like 1347/1270, that being sensors 1/2… is this normal? it seems overly hot to me, i was standing behind the car while it idled and the exhaust felt a lot hotter than i expected… is this overly hot? and if so, what would that be a symptom of?

    thx in advance for any insight friends!
     
    #1 viciousthinker, May 13, 2025
  2. Tombukt2

    Tombukt2 Senior Member

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    Seems a bit high . Might look at fuel delivery .
     
    #2 Tombukt2, May 13, 2025
  3. rjparker

    rjparker Tu Humilde Sirviente

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    There are no sensors, those temperatures are estimated. If you have a P0420 or are burning a lot of oil the cat may be getting clogged or you might look at fuel trims as Tom suggests.
     
    #3 rjparker, May 13, 2025
    Brian1954 likes this.
  4. PriusCamper

    PriusCamper Senior Member

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    Yeah... Seems you have to confirm or deny those temp readings. Maybe using a thermal camera to get reading of metal temperature from exhaust header to tailpipe.

    Any other symptoms like bad MPG or sluggish engine performance?

    Also the EGR system helps lower engine combustion chamber temperature for cleaner burning, but they tend to clog quickly due to a faulty design in Gen3 Prius. Have you ever had yours cleaned?
     
    #4 PriusCamper, May 13, 2025
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