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ford hall effect sensors.

posted Jun 16, 2016 22:47:26 by Inge_Jeppesen
Lately I have seen hall sensors with 5 volts and ground, that on the signal wire, it pulls a 12 volt to ground from the computer. Cam, crank. Rotation sensors on window motors. Are these used on few cars, or common to many models?
Norway
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2 replies
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Chris said Jun 17, 2016 21:12:11
I don't know about Fords set up but it sounds believable. Ran into a great little self case study last night on a C-15 CAT diesel. Had a IVA pressure sensor voltage high or shorted to B+. I checked power 5.05. Ground 0.15. Signal 5.05v. << not good.

I unplugged the sensor and the signal wire suddenly had 11.5 volts on it. Bias voltage I'm sure. Reading thru the TS tree CAT has and it states the ECM uses a pull up voltage to detect sensor issues. So...? I always thought a bias circuit was a pull down design. If the ECM sees high voltage= problem, low voltage= problem and voltage in a spefic range it's ok.

Grabbed a new sensor and plugged it in and the signal was at .56.
Which in my opinion is where it should have been. Code cleared and all was well.

Now here is what blew my mind. The trouble shooting tree says to check voltage at the signal wire unplugged. It should be less than battery voltage. If not the signal wire is shorted to B+. but if less than B+ it's ok. My B+ was 12.5 and my signal wire read 11.5 so I was a little lost as to if that was ok. I'm unsure how CAT runs their bias voltage but I'm digging deeper into it tonight.
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Dylan said Jun 18, 2016 11:18:10
Now here is what blew my mind. The trouble shooting tree says to check voltage at the signal wire unplugged. It should be less than battery voltage. If not the signal wire is shorted to B+. but if less than B+ it's ok. My B+ was 12.5 and my signal wire read 11.5 so I was a little lost as to if that was ok. I'm unsure how CAT runs their bias voltage but I'm digging deeper into it tonight.


Nice one Chris. Kinda confusing. I'm interested in what explanation you can find on how this system works.
Belgium, Europe
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