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P1436 Error code

Discussion in 'Generation 1 Prius Discussion' started by ZTE, May 2, 2021.

  1. ZTE

    ZTE Junior Member

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    The cat on my Gen1 was stolen recently and I was able to find an OEM replacement. However it did not come with the HCAC valve that goes on the top. Because of this the car throws up a CEL and gives me the P1436 error code.

    Is there anyway to trick the car into thinking its there/functioning? From what I understand the car seems to throw up the code whether the valve is stuck open or stuck closed, so plugging the vacuum line doesn't make it go away. Is there a sensor somewhere that can be given a specific voltage or possibly removed/bypassed in order to make the error go away?
     
    #1 ZTE, May 2, 2021
  2. ChapmanF

    ChapmanF Senior Member

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    There's such a thing as an OEM replacement without the HCAC?
     
    #2 ChapmanF, May 2, 2021
  3. Travis Decker

    Travis Decker Active Member

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    They are a seperate part and on backorder.

    Get a used one?

    I just asked a cat recycler to start saving them for me
     
    #3 Travis Decker, May 3, 2021
  4. ChapmanF

    ChapmanF Senior Member

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    #4 ChapmanF, May 3, 2021
  5. nimblemotors

    nimblemotors Re Member

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    You can make it go away by putting a smiley sticker over the check engine light. :)
    That won't let you pass the smog check though.
    I was wondering the same thing myself, how does it know its not working?
    My guess would be it measures the pressure in the switch. Or it could measure the o2 sensor readings?
     
    #5 nimblemotors, May 3, 2021
  6. ZTE

    ZTE Junior Member

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    This was my thought as well. However i dont see how it could be related to the 02 sensor, since the sensor is located before the valve and not after it.
     
    #6 ZTE, May 3, 2021
  7. nimblemotors

    nimblemotors Re Member

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    Found the switch for the vaccum hose is in the engine compartment on right side by throttle body. Perhaps could try and put a little diaphram on it and see if that works to stop the error?
    The 02 could possibly detect the downstream change.
     
    #7 nimblemotors, May 3, 2021
  8. ZTE

    ZTE Junior Member

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    Ive never tried to plug it at the engine end before. I believe the line comes in at the T Valve near the oil dipstick?

    Putting a diaphragm on it is an interesting idea. It is my suspicion though that there is probably more involved in the detection mechanism.

    I was able to get the P1436 code to clear by messing around with plugging/unplugging the hose a bit but the car threw up P1437 instead, which i believe is a more specific error related to the valve being stuck closed.
     

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    #8 ZTE, May 3, 2021
  9. nimblemotors

    nimblemotors Re Member

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    Well that is progress! So it must be sensing the pressure changes if it plugging it changed the code.
     
    #9 nimblemotors, May 4, 2021
  10. nimblemotors

    nimblemotors Re Member

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    Here is where its located Near the DRZ-A and BH2, behind the GRG/KN and PT. TLA GL :)
    [​IMG]
     
    #10 nimblemotors, May 4, 2021
  11. ZTE

    ZTE Junior Member

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    #11 ZTE, May 8, 2021
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