I know I have an issue with my EOT sensor wiring. I need to know where the two wires lead to and the id markings.

I have had this issue before, a couple years ago. Not sure where witch wire was rerouted. ( going to have a couple days to work on it next week) vacation time.
Sometimes the truck's EOT is lagging behind the ECT, then when it catches up will bounce up and down quickly, Then other times it will be equal to the engine temp. Sometimes when this happens the fan will rev up even with the engine not even close the operating temp. Other from that the truck run great.
I am going to replace the sensor just in case.
Any help with this is appreciated, or any other suggestion to watch for.
ex. wiring colours, voltage reading at both, with and without engine running.

 

You want page 26-8 lower right for the EOT wiring.

I thought I had the connector diagram but I don't.
If you find you can't do without let me know and I dig it up.

 

Oil & coolant temp sensors are same. You can swap them and retest to see if the problem follows the sensor. If it does follow the sensor then the sensor is to blame.

 

thank guys.
I forgot to say I get a P0198 code.

 

Regarding the EOT sensor. The Lt grn/red wire goes to the PCM where does the other wire lead goto?

Thanks

 

Both do. One is the Vref and the other is the signal return.


LG/RD is Vref
GY/RD
Just use common power flow and thinking of the GY/RD as ground.

It will drive most people nuts trying to use Electron Flow to think about this.
You can stick with conventional.

If you want to hurt some brain cells look here.
https://www.allaboutcircuits.com/tex...electron-flow/
https://www.mi.mun.ca/users/cchaulk/.../ivse/ivse.htm

 

pulled the eot sensor.
resistance shows an amazingly high 45.6 olms in auto range.
I know its too high. I think is should be around 2.5 olms. Is that right?
Holding the end by hand started to drop to 30 olms in less then 30 seconds

I'm ordering a new sensor.

 

 

Check a couple outer thing.
Unplugged the eot. while engine was running the olm readings dropped. ECT = 122f, olm reading was 11.2.
With the eot sensor unplugged wired one lead from the sensor to my meter the other end from the sensor to eot plug then from the other lead (plug) to the meter, i was getting 5.0v reading without any change (engine running at 120f).
I think I have a wiring problem.
Cancel a new sensor.
History a couple years back I had this same issue. A Ford tech mechanic (mchan68) found a wire to the PCM was broken somewhere. So he ran a desperate wire from the sensor to the PCM. I was not able to find any break in that wire. If I followed the other lead (not to the PCM) where will it go?

 

That is Vref so 5.0v is correct.

I am guessing are you talking about the
GY/RD ? That would be going to a signal ground that ends at
​​​​​​​the PCM but may go other places first.

 

So where does the other one go to?
One lead goes to PCM (ground signal) and the other one?????

So a constant voltage of 5v. The sensor resistance decreases as the oil heats up and the other lead goes to..........
I want to understand.

Thanks for your helping hand.
​​​​​​​

 

What color wire are you trying to find the location for?
I have the other truck here and can do some snooping on it.

That of if you want to call me later you can. It's that cross the
border part that tends to drive the call price up.

 

It's a series resistor circuit.

 

Thats the problem I had a pigtail replace the original plug.
I don't know what wire color has been replace going to the PCM.
My reading the schematic drawing shows that both wires are going to the PCM. Please walk me through.

Thanks

 

Both wires do go back to the PCM.

One is the ground circuit which is spliced in with the other sensors and controls, pin 44, wire color gy/rd.
The other is the voltage reference and reading, pin 25, wire color lg/rd.

What color wire Mike used for the lay-over, god only knows.

My arrow didn't quite match up.