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I have a 2011 Ford Fusion with the 6 speed trans.

How do I replace the transmission temp sensor? I'm throwing code p1783.

Engine: 3.0L. Transmission 6 speed semi automatic. Miles ~115k; Bought @ 53k. Had regular transmission flushes since then. Last one late 2015 @ maybe 70k. Have never replaced engine coolant but most mechanics have told me they don't even do that.

Symptoms: Wrench light comes on after 15 - 30mins of highway driving at speeds of 80mph or greater (totally okay on Chicago freeways).

When wrench light is on, fan up front is loud (notice it off hwy) and the throttle is touchy and seems to loose power. Touchy to the extent of it feeling like its slamming into a brick wall that isn't there (at times it's this bad).

I haven't checked the actual level but the fluid is red and doesn't smell burnt. I'd assume I'd be out of tranny fluid if it was leaking due to this being an ongoing issue since JAN 2016.

After 3 miles of off hwy driving, light comes off throttle acts fine, fan revs down. No codes are stored after the fact and the code has to be caught with the light on. I have a bluetooth odb I pulled it from.

Consulted with several people. The only two suggestions I get are vacuum leak and temp sensor.

Thanks.

Quesofat
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2 Answers2

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First and foremost, check the fluid level. Ensure it has enough, but NOT over full.

Check the transmission lines to the cooler (radiator) to make sure they are not damaged or pinched off. If there are no obvious physical issues that you can see, it is time to have it serviced. They can check internal fluid flow and pressures.

I don't think it is a sensor because it is sensing the over temp condition and running the fans. I also don't think it is a vacuum leak because that would be evident thru all modes of operation.

Since the highway stress causes issues and street driving allowed better performance, I am leaning toward it is not able to cool properly. That can be caused by low fluid or blockage to/from the cooler.

CharlieRB
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If anyone comes across this for a 2011 Ford Fusion SEL. The issue was fixed by ensuring the transmission fluid levels were correct and more importantly a SOFTWARE UPDATE was done. Magically, the transmission ran a lot cooler.

Quesofat
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