2000 F-150, 4.6 V8 triton, automatic transmission. I keep getting this code, I have changed out the ECT (Engine coolant Temp. sensor), changed out the Thermostat, and I have drained,flushed and refilled the coolant. The codes clears for a week or two than it come back. Is there anything else that might trigger this code, this is getting to be a pain in the my rear bummper!

 

Have you checked the cooling system for air pockets?

 

No I have not looked for air pockets, and the reason I have not, is I have no Idea how to look for an air pocket. So I ask you to please help me,

 

Take the coolant reservoir cap off when the engine is cold. Top off the reservoir if needed. Start the engine and let it warm to operating temperature. When the thermostat opens if there is air in the system, it should burp out and the collant level will drop. Refill the reservoir and repeat the process till all air pockets are gone. Good luck!

 

Alright I checked for air pockets and I believe the system is free of any air, I let it run for about 30 to 40 min. while checking for air. The bad news is that I still have the P0125 code. I am open for new suggestions on what might trigger this code. I think I will change out the thermostat and ECT sensor again, there is a possibility that one is still bad.

 

From FORD diagnostic references:

P0125
Insufficient Coolant Temperature For Closed Loop Fuel Control
Detailed Description
Indicates the ECT or CHT sensor has not achieved the required temperature level to enter closed loop operating conditions within a specified amount of time after starting engine.
Possible causes :-
Insufficient warm up time.
Low engine coolant level.
Leaking or stuck open thermostat.
Malfunctioning ECT sensor.
Malfunctioning CHT sensor.(Cylinder Head Temperature)

================================================== =============

Thermostat Monitor

The Thermostat Monitor is designed to verify proper thermostat operation. This monitor will be phased in on certain applications beginning with the 2000 model year and replaces the original "Insufficient temperature for closed-loop test" (P0125). This monitor will be executed once per drive cycle, after a two hour, engine-off soak period. If a malfunction is indicated by the thermostat monitor a diagnostic trouble code P0125 will be set and the malfunction indicator lamp will be illuminated.

The monitor checks to see if the engine is being operated in a manner that is generating sufficient heat. While the engine is at moderate load (greater than 30%) and the vehicle is moving (greater than 15 mph/24 km), the ECT or CHT should warm up in a predictable manner, therefore, a timer is incremented. The target timer value is based on ambient air temperature at start-up. If the timer exceeds the target time and the ECT or CHT has not warmed up to the target temperature, a malfunction is indicated.

The target temperature will be calibrated to the thermostat regulating temperature minus 20°F (11°C). For a typical 195°F (90°C) thermostat, the warm-up temperature would be calibrated to 175°F (79°C).

1. Inputs: ECT or CHT, IAT, engine LOAD (from MAF sensor) and vehicle speed input.

2. Output: MIL.

 

Thanks for the diagnostic references sheet!!! But here is the rest of the story, the engine is a 97' 4.6 triton that was put into a 2000 f150 body, every thing matched up and the truck runs great. the only thing is that the 2000 F-150 has the ECT harness and the electronics, the 97' engine does not have a place to screw in the ECT or CHT whichever one that goes in. So as of right now the ECT is resting wedged in next to the cylinder head. I need a Ford guru to give me some advice on what is the best plan of attack. If you really want to help me I will give you my e-mail address and then my phone # so we can talk and exchange ideas. Thank you!!

 

[QUOTE=cajun1965 So as of right now the ECT is resting wedged in next to the cylinder head. I need a Ford guru to give me some advice on what is the best plan of attack.[/QUOTE]

So, in fact, you know why it's throwing the code.

My reference indicates the '97 has CHT & ECT sensors. The '97 was from a truck, right?

But...... even the '97 Crown Vic has the two sensors.......

Maybe a Ford tech can step in here.............

 

The truck ran for about a two months with the 97' engine and there was no code but then it just came on. as far as where the engine came from, I believe the guy who got the engine said it came from a Lincoln auto. I am not 100%. Is that possible? But this engine does not have a place to put the ECT. The way the wire harness runs it looks like it belongs on the drivers side head right above where the thermostat is. I know this sounds strange, but like i said everthing else matched up and the truck runs great.