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Ohm Testing Parts

Discussion in 'Gen 2 Prius Main Forum' started by Mark Iris, Jan 15, 2021.

  1. Mark Iris

    Mark Iris New Member

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    I have a stupid question on how to test ohms (I'm testing my O2 sensors). The Prius manual says prongs 1 and 2 should have resistance between 1.8 and 3.4. Ok, that makes sense. Then, the specified condition for prongs 2 and 4 should be "10 kohms or higher". What does that even mean? Isn't that just a setting on my multimeter? What am I supposed to be testing at prongs 2 and 4 or what sort of resistance should I be looking for?
     
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    Just an FYI, you're moderated for five (5) posts. This is 10,000 ohms (10k ohms), and should be a setting on the multi-meter.
     
  3. PriusCamper

    PriusCamper Senior Member

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    Let us know how this ends up working out... You've raised an important thing that others would like to learn, so once you get it figured, let us know?
     
  4. Elektroingenieur

    Elektroingenieur Senior Member

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    The quantity being measured is resistance, and the ohm (Ω) is the unit.

    When the Repair Manual specifies “10 kΩ or higher,” set the meter to measure resistance on its lowest scale that includes 10 kΩ. For example, if you had a very inexpensive multimeter like this one, you’d select the 20 kΩ scale:
    63759_W3.jpg
    If you have an auto-ranging meter, you’d just select resistance (Ω).

    The actual resistance might be much higher than the selected scale, in which case the meter display might show only “1,” “OL” (overload), or whatever it shows when the meter is in resistance mode and the test leads are disconnected or not touching anything. That’s fine, since you don’t need to know the actual value of the resistance, just that it’s “10 kΩ or higher,” meaning the part is OK.

    You might wonder, though: if the meter display didn’t change when you touched the test leads to terminals 2 and 4 on the part, how do you know the leads are good? It’s usual, before making a resistance measurement, to touch the tips of the two leads together and see that the meter reads zero, or if it’s on a scale low enough to measure the resistance of the leads themselves, less than about 0.2 Ω.
     
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  5. Mark Iris

    Mark Iris New Member

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    Yes, I have a setting on my cheap multimeter for 20KΩ, so I set it to that, and then what resistance am I looking for between terminals 2 and 4? Are you saying it should display "1" or "OL" and that means it's working, and any resistance like 0 or anything less than 10k means its not working, or not within the specified condition as outlined in the manual?
    Here's a picture of what I'm talking about:
     

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  6. Elektroingenieur

    Elektroingenieur Senior Member

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    Yes. A meter reading of 10 kΩ or higher means the part meets the specified condition. This could be a reading of exactly 10.00 kΩ or some higher value, or it could be an off-scale high reading (however that’s shown on your meter), meaning that the resistance is more than 20 kΩ, the selected scale. If the reading is zero, or any value less than 10.00 kΩ, the part is defective.
     
  7. Mark Iris

    Mark Iris New Member

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    Got it, thanks all!
     
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