5v Reference Circuit problem (maybe) (FIXED)

do you have the ohm spec for the sensor that's acting up? try putting a resistor in and see if the pcm reacts with the correct temp??

GeorG wrote:

borntoroll wrote: Check ohms

Could you be more specific to were I should check ohms please? :huh:

ECT1 cold and when fans kick on

Well, the car is fixed.

Borntoroll and cheryl hartkorn were dead on, I checked the sensors resistance and it had the same resistance as the ECT 2 which is a completely different part number, plus I used a resistance box to "simulate" the ECT 1 sensor resistance and the scan tool showed the correct temperature per AllData specs.

Now I know where I took a wrong turn in my diagnostic strategy.

The other shop had already "tried" two (new) different ECT sensors which lead me to "believe" it wasn't the problem. Another thing that added confusion was the fact that once the ECT 1 was disconnected, the signal wire had less than 5 volts(4.6), while the other sensors had 4.9 or 5 volts minimum.

I think we just found an exception on the 5 volts we are so used to find when we disconnect a thermistor. Like Danner says, "always and never" shouldn't be part of our language

I will most likely upload this case study (YouTube Video) and other ones I have in the near future.

Thank you all for your time and help.

sweet. hope you upload it to youtube... whats the name to look under on there??

Great to hear! :woohoo: Another case of an installed problem... Why were they swapping temp sensors in the first place? :huh:

For what it's worth, I don't think you made a mistake pursuing the 4.69V. I saw that as a red flag, too, and totally thought you were on the right track. Your diagnostic path took A turn, just not a wrong one IMO.

Tyler wrote: Great to hear! :woohoo: Another case of an installed problem... Why were they swapping temp sensors in the first place? :huh:

For what it's worth, I don't think you made a mistake pursuing the 4.69V. I saw that as a red flag, too, and totally thought you were on the right track. Your diagnostic path took A turn, just not a wrong one IMO.

Thanks Tyler.

cheryl hartkorn wrote: sweet. hope you upload it to youtube... whats the name to look under on there??

Like I said earlier, in the near future because I don't have a youtube channel currently, but I'm planning to have one

Since my native language is spanish, I'm thinking of doing a bilingual channel. I still don't know but I'm really hoping it turns out ok.

Any suggestions are welcome.

Good deal, glad you got it sorted out!