2001 Ford F-150 5.4L Triton 'service engine soon' light on with OBD-II saying P0125 Insufficient Coolant Temperature For Closed Loop Fuel & dashboard temperature gauge won't raise much above cold level.

Help!!!

I have an Engine Coolant Temperature sensor (ECT) Part# F5AZ 12A648 AB onhand. Will this correct the problem? Where is this sensor located??

 

Is the upper radiator hose hot to the touch? Are you getting hot air from the heater?

Sounds like your thermostat may be stuck open.

 

Yes. Definitely getting hot air from the heater, but dashboard temp. gauge not reading much higher than C(old) for some reason??

 

Try a thermostat before the ECT/CHT.

 

Got talked into buying the Engine Coolant Temperature sensor (ECT) Part# F5AZ 12A648 AB before the thermostat

Also, my speedometer seems to be reading much higher than normal & malfunctioning. Is that normal?

Where is the ECT located, just in case?
Is the thermostat available at any autoparts store? What's it called exactly? Where is it located?

Thanks for any assistance & patience.

 

Yes, it should be.

Just "thermostat" If the 2000 5.4 thermostat is the same as the 4.6, you can use AC Delco thermostat #12T31E2. You'll also need the o-ring, Felpro #35489. (When you take the old one out you'll see where the o-ring goes.) These two parts together should cost around $12.

Pretty much front and center on the motor. Follow the upper radiator hose back from the radiator. It connects to the thermostat housing. You will need to loosen the bolt that holds the power steering reservoir bracket to the thermostat housing, then remove the two bolts that hold the thermostat housing itself.

It's a pretty simple repair. From your description, it seems very likely that the thermostat is the problem.

~Ed

 

Thermostat replaced & problem resolved! Thanks for all the help!

Anybody neeed the Coolant Temperature sending unit??!!! I didn't need it. Let me know.