I have a 2001 ford expedition 5.4l. I have thrown a P0125 code and I have purchased a new thermostat as well as the ECT sensor. I have found that this sensor is often called a CHT sensor. Are they they same thing? I have opened my hood, and I know very little about the workings of an engine, and I am lost with all the wires and things I see. I know I need to remove the black cover on top and somewhere on the driver side I should see where this sensor goes. Can someone please help me with an actual pic of my engine? Use a screw driver or something to point at the sensor location. I also need to know where the thermostat goes. I admit I am the typical girl lol but I want to learn this for my new truck. I drive across the state every month for medical appointments and I would like to make sure me and my kids are safe. Please help!

 

Were you repaired, then got lost ? Or are you still broke without direction ? jk... Okay, a bad one then.

P0125 Insufficient Coolant Temperature For Closed Loop Fuel Control

Regardless. You vehicle doesn't have an ECT. Those were deleted from 1999. The CHT took on the ECT programing. It was added to the CHT reporting.

Do you have heat. Put your hand on the rubber hoses that disappear into the firewall after it's been running. Are they warm or hot to the touch?

It's probably the CHT sensor ( inside front of the drivers side head.), - usually you get a circuit DTC along with tho. It's a good size job replacing those. Unless you have small hands and a little creative. If so, you can remove the alternator to get to the sensor, bust the top of sensor off to remove it. Thread the new part in as tight as you can get it, plug it back in.

Other than, you'll have to remove the intake to get at it easily.

 

A P0125 is usually a failing thermostat. They stick open a bit and keep the engine from warming up as fast as it's supposed to.

Replace the thermostat and refill the coolant. You don't need the sensor based on that code.

 

I just replaced my cht over the last couple days. You'll need more patience then mechanical skills for this. The sensor is just under and to the right of the alternator, back under the intake manifold. You can't see it, but you can follow the wire with your fingers and touch it. The real way to get at it is to remove the intake, but this takes a lot of work, time and more parts. I removed the air intake tube (air filter tube, not the entire intake manifold), the top plastic cover that says 5.4 triton, and the alternator only and managed to get at mine with a 3/4" wrench. It's a bitch to say the least because you can only turn the wrench a small amount before you have to turn it over and turn it another smaller amount. Slow process, and you have to be VERY carefull or you'll pop the electrical connector right off the sensor like I did. Make sure every time you put the wrench back on the it is down all the way and catching the hex bolt, not the connector. It's really a simple repair, but made to be a PITA by the location of it. There are pictures to be found, but not really needed if you follow the wire that heads under the intake, under/beside the alternator.

EDIT - JBREW makes a good point to break the existing sensor's electrical connector off before removing it. It will allow you to wiggle a short 1/2" drive 3/4" socket over it, making removal much easier.

 

Hi Dream. I admire your desire to learn and do this yourself. However just a few words of caution when working on any vehicle there are certain safety issues you should be aware of. The big one I see here is that a person can get severe burns if removing the coolant hose while the engine is still hot. You probably already know this but the coolant system is also under pressure and must be drained at least enough to allow the upper end of the system to be empty. Even if it has cooled down spilling coolant all over the top of your engine can create more problems if that coolant gets in and around the COP's. Refilling these engines with coolant can also be a little tricky and if not done right can cause other engine problems. I never want to discourage anyone from trying their own repairs especially a lady (some of the best automotive engineers I knew were women) but I think you should know that there are potential safety and driveability concerns that go along with your decision. Always weigh the cost of repairs both in safety and the possibility of making a small problem into a much bigger and more expensive one. Good luck

 

Yea, posting it's "probably the CHT" was bugging me a bit;- it wasn't a circuit DTC. Right, it might be a thermostat issue, but, - that DTC has come up on vehicles here and there in the past and what the problem ended up being.... They were just low on coolant.

Dreampxie2000 - Check your coolant level first. There's a "Hot and Cold" line mark on the transparent bottle next to the radiator, drivers side. DON'T open the bottle if the vehicle s engine is still warm. Wait for it to cool.

Take a flashlight, look at the outside of the bottle to see your coolant level.

 

Thanks everyone for the help. I'm going to give it a go this weekend. No JBrew not a DTC error. I get heat-ish from the heater. It has never gotten more than warm. Believe me when it's sitting at 28 degrees outside I wish it were warmer. I only got the p0125 code. Funny thing is I get the idea of an engine an can usually know what's goin on by the way my truck or vehicle drives and sounds! Friends have had issues and I can usually tell them what I think it is an then find out from their mechanic I'm right. Lol who knew. But looking at the cluster f* under the hood eludes me. I know what an alternator looks like as I've done that before. 4 bolts easy. I can change my belt as I had to. My exhusband(absent any mechanic know how) spent 8 hours fighting it. At the time I had a brand shiny and new car and I didn't want him to drive it so I went out and in 15 minutes figured out grove belt side to groves pulley and smooth side to smooth pulley. Now granted I was a little perplexed when it didn't go around so I took a wrench and discovere the tension pulley. Popped on and done. So in short I'm confident I can give this a go. Thank for telling me to break it first, but any advice on not breaking the new one. I'm gonna go ad head and replace both the CHT an the thermostat so I only need to get in here once. BTW Chiltons doesn't help when I can't understand for the life of me what language it's speaking. It appears to be English but that's debatable. Lol. I'll let you guys know how it goes.

 

Do NOT waste your time on the CHT sensor, it is not at fault for this fault code. There is no need shoot the messenger when all you have to do is read and decode the message.

Replace the thermostat and refill the coolant like I said. Call it a day.

For further explanation of the code and how to troubleshoot it, consult the factory PCED and the Ford OBDII manual.

 

Make sure your not low on coolant, - like I said.

Then go for the thermostat..If needed. Simple things first.

 

Do you have a repair manual for your truck? Even a Chilton or Hayes manual is better than nothng.. It will usually give you detailed instructions for removal and installation of most of things under the hood.

They have pics of the specific part you are hunting for and yes, while they do cover multiple years of vehicles, most of the parts are where they describe in the books.

Good luck with it all! We all had to start by looking under the hood and wondering WTF...

Mitch

 

^^^

 

Just check the coolant level.. It's easy..Honest.

 

The cheapest fix for this problem is to cut a large piece of cardboard (maybe 18" x 18"), remove the plastic cover over the radiator and drop the cardboard between the radiator and condenser. I've done this on my 2000 F150scab 4x4, 5.. It fixed the problem, stayed in place all winter in Wisconsin and I removed it in the spring.

 

A piece of cardboard isn't going to fix a low coolant condition or a stuck-open/leaky thermostat.

 

First off I completely agree the repair should be done in the following order:

1. Check coolant level
2. If coolant level is good, replace thermostat, clear codes and drive.
3. IF code returns, then MAYBE CHT.

Second, I thought from the title some guy lost his girlfriend during a repair