Service Engine light came on, replace ECT Sensor?

[Aero540T]

I've got an '03 XLT with about 84,000 miles on it and as of a couple days ago started throwing the Engine Coolant Temperature Sensor code. I had it read for free at AutoZone...really glad I took it there rather than have the dealer charge 75 bucks to read it.
Anyways the guy said that either the coolant was low or the sensor is failing or the wire is grounding out.

The coolant was a bit low so I put more in it, let it cool down, then put some more and the CEL is still throwing the code. Should I just get a new sensor?
I can get the parts wholesale from work and put it in myself rather than taking it to a shop, but I want to make sure this is the correct next step first.

 

[Glacier991]

Check the wiringto the sensor for chafing and the connection at the sensor for corrosion. If it all looks ok then replace the sensor.

 

[BrooklynBay]

What was the code it was throwing? Maybe the engine was cold when they performed the diagnostic. You could check the sensor with the following chart:
Dead Link Removed

 

[Aero540T]

I drove the truck about 10 miles straight to AutoZone from work so it should have been pretty warm still by then, but I forgot to ask for the number code, he just told me it said the coolant temperature sensor one was going off (I forgot his actual wording of it).

 

[Aero540T]

Well I've got a little update here, I got the new sensor from NAPA through my boss and I worked on the truck today.

I drained the coolant and removed the old sensor and was about to put the new sensor when I noticed this:
New on the left, old on the right.

Was there a mixup at NAPA or is something else going on here?

Anyways I put new coolant in and the service engine light went off...so I guess I didn't need a new sensor (I just cleaned the old one off and put it back in). Maybe it just wanted new coolant?
I guess I'll just return the new sensor to NAPA

I forgot to add, I disconnected the negative cable from the battery like it said in the Haynes manual (didn't think it would matter tho), but would that make the computer reset and turn off my Service Engine light?

 

[BrooklynBay]

Disconnecting the battery clears the codes temporarily until the problem is solved. The part on the left is the most common design. The one on the right isn't familiar to me. Replace the part with the new one. How much was it?

 

[Aero540T]

Disconnecting the battery clears the codes temporarily until the problem is solved. The part on the left is the most common design. The one on the right isn't familiar to me. Replace the part with the new one. How much was it?

Does that mean the problem is still there but now the code won't show up? Or will it come back on?

Anyways, this doesn't make sense to me, I mean it would be nice to use that new sensor but there are no threads at all in there. How am I supposed to put it in?
The old one just pushes in and there is a clip that grabs onto the ring you see in the picture a bit below the rubber piece. I did try to still put the new one in but the clip isn't made to grab onto threads so I can work the sensor out easily with my fingers.
My boss gets parts either wholesale or discounted since he's a Ford dealer (antique Fords), so I only paid $15.01

 

[BrooklynBay]

I overlooked the fact that it was missing threads. I was looking at the odd shape of it compared to the threaded version which is more common. I mostly work on older Fords. Your vehicle is a 2003, so they might have changed the design on all of the newer ones. Have your boss try to get it for you.

 

[Aero540T]

I overlooked the fact that it was missing threads. I was looking at the odd shape of it compared to the threaded version which is more common. I mostly work on older Fords. Your vehicle is a 2003, so they might have changed the design on all of the newer ones. Have your boss try to get it for you.

Thanks for the help, I guess I'll just ask my boss tomorrow and hopefully NAPA has the one I need. Even the Haynes manual said to "unscrew" the sensor, but it also said to remove the clip...doesn't make sense to me since it would only need the clip if it didn't have threads, the one that has threads wouldn't need a clip. damn Ford