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Coolant temp sensor testing needs to be done at all different temps?

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Coolant temp sensor testing needs to be done at all different temps?

Old 05-02-2019, 11:14 AM
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Coolant temp sensor testing needs to be done at all different temps?

Or can I assume the ECU coolant thermo sensor is OK if it's within specs at the current temp?

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Last edited by Paul22RE; 05-02-2019 at 12:18 PM.
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Old 05-02-2019, 11:46 AM
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I personally have had a HONDA coolant temp sensor fail and make the system think it was incredibly cold out, but the reading was still within the realm of possibility. So i'd take a couple readings at least, one cold and one at the temp you think you are experiencing the problem at.
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Old 05-02-2019, 11:54 AM
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The coolant temps sensor is not a switch, it's a thermistor. (But you knew that, because you were testing resistance.) http://web.archive.org/web/201311071...40engineco.pdf I don't "know" if you can make that assumption, but that's the one I would make. The failure modes that I can think of would all pull the measurement out of spec at room temperature, and pretty much any other temperature.

But if the sensor is out, my curiosity alone would make me dip into some boiling water.
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Old 05-02-2019, 08:28 PM
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Yep, measure resistance while dipped in boiling water and then while dipped in crushed ice.
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