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Junior Member
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6 Posts
Discussion Starter #1
I am lost in the flash or replace the pcm or whatever else.
Recently my tuck was diagnosed with oil cooler failure at a local shop,so I replaced it my self all went back together like it should,I got it started but it went into limp mode.I put my scanner on it and got the P0118 code,which is input circuit high so I change ect.Same code same problem,but. now it wont start.I have tracked the wire and rewired at the pcm,then checked the volts from the pcm to Ect and got 12.my truck is a 05 f250.if anyone can help or just has an idea please don't hesitate. Thanks Derrick
 

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Old Fart
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889 Posts
Your description is not entirely correct. "P0118 - Engine coolant temperature High, input" This is the temp sensor for the coolant. The pcm is not adding 12v to this sensor, it is the sensor that is telling the pcm that the temps are high. Don't mess with the wiring, but changing the coolant temperature sensor is advised.
 

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Junior Member
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6 Posts
Discussion Starter #3
Dave thanks for your response.I have replaced the ect it was my first step when I got the code.Is it possible the new part is bad also it is a duralast part from AutoZone.
 

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Senior Member
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3,051 Posts
Because this all started occuring since your oil cooler swap, makes me think that either a wire is crossed, like the wrong connector is plugged into the ect sensor, or maybe the wiring harness is chaffed somewhere causing the false reading.

What happens if you unplug the ect sensor? Does it still throw the code PO118?

Also, is the wire circuit to the pcm possibly shorted to ground? Most ect sensors use a variable resistance reading to ground to determine temps, especially if it's a single wire circuit.

Could also be shorted to another wire due to chaffing in the wiring harness which may have been induced during the oil cooler repair.

A faulty pcm would be the last resort and least likely probability, I see this on occasion though, where the pcm throws a false fault code that won't erase for a given sensor even though all is ok, but that is very rare.

Make sure you are using the correct wiring diagram for checking and testing.

Harry
 

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Junior Member
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6 Posts
Discussion Starter #7
Thanks for the input.I was told that the harness had a recall.I am going to change it but I really don't know what to call it.I call the ford dealer trying to figure out what to call it but parts guy couldn't figure it out.all my sensors and plugs look horrible frayed and bare in spots.all that being said where is the best place to get one and what should I ask for.Thank you very much.
 

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Senior Member
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3,051 Posts
1. Engine wiring harness to the pcm is what I would call it.

2. Ford dealer would be the only place I know of to get a new harness.

3. There was this recall below that might apply to your truck...

Ford Motor Co. is conducting a safety recall involving 2004 and 2005 model year vehicles equipped with its 6.0L diesel engines to address reported incidents of engine stalling while driving. The action covers 180,000 of its E-350 and E-450 vans, F-250 through F-550 Super Duty trucks, as well as its Excursion sport utility vehicle.

Ford dealerships will upgrade or replace the fuel injection control module wire harness, and/or have a new injection control pressure sensor connector installed, according to Ford.

Harry
 
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