Truck is a 2001 Ram 1500 5.2L 4x4 No tuners.

Well this code has been coming on sense the cold weather. I have no idea what is causing it. It runs maybe 160-170ish.

I have tried the following.

-Coolant Flush
-3 Different Thermostats
-A Clutch for the mechanical fan
-Coolant temp sensor (was broken in the process of repair something else.)

I still dont know whats causing it, and its preventing me from getting a good inspection sticker.

Any ideas?

 

Is the t-stat installed in the correct direction? Also check the fan clutch(could be defective new one,doubt it though) . Also you are using a 195 stat and tested it before putting it in right?

 

New IAT sensor.

 

Yes it is a 195 degree t-stat.
The fan was considerably better than the new one.

Also how would changing the IAT sensor make it run hotter? I belive it could be true but dont understand the logic behind it.

 

two fold the reasoning:

an IAT, properly reading, will lean out your a/f if it is called for, and THAT by itself will raise the temperature...

you may NOT be running cool.. unless you're pulling live data, you don't know for sure if the coolant is the 'too cool for too long' culprit.. it could be that the engine is expecting the air to be warmer based on the contrast to coolant temperature, and not allowing the sensors to start dictating variables (doesn't go closed loop).

I had a p1281 for a long while.. and after swapping the IAT, I haven't seen it since. It's not expensive, and it only takes a second to swap.

 

The IAT has nothing to do with your situation.

 

I'm not meaning to argue with you Zman.. All I can say is that I researched the IAT as much as I could and found out a few surprising things about it.. I really didn't think it could have bearing either- but I swapped it, and the p1281 hasn't shown up since.

since swapping the keg for an FI, and having to relocate the IAT, I had issues.. I went round for round with that thing.. the temp gauge on my truck differs from the one on y'alls- so I can't compare temperature readings- but it read between 1/4 and 3/8 or so..

it still does.. but with a new IAT, I've yet to see the p1281.

that thing DOES have bearing on your fuel trim.. and a leaner engine runs hotter than a richer engine.. THAT, is pretty much my basis for rec'n he swap it out..

I think it was something like $15 from a dealer..

 

so the 01 with a single temp sensor is registering only 160'ish on the gauge,
and you've replaced the temp sensor
and you've replaced the t-stat 3 times..
and it still runs cold.

either all t-stat's are bad.
or you're not seating them in the well correctly, or they're not sealing.
or both temp sensors are bad.
or the wiring or pcm is damaged and misreading the signal from the sensor.
or its -100 degrees where you live.

you could check the actual engine temp with an handheld heat detect/meter.
you could investigate what the temp sensor output voltage (or ohms?)should be, and measure that with a voltmeter.
inspect the wiring from the sensor to the pcm. any mouse chewing, corrosion, damage.
run the cluster test on your 01. hold tripmeter reset in, while turning key to on. it will run each gauge up to 1/4, 1/2, full.
clear the code by resetting pcm. disconnect negative battery and turn on headlights for 30 sec. caution - this will require about 100 miles of CEL free driving to get the pcm to a ready condition for emissions testing.


now i'm guessing - a real time data scanner might show a flawed reading somewhere (including maybe IAT????, maybe it plays in somehow by factoring the temp sensor reading up or down??? who knows)

 

Not a problem man, just saying I don't think it is his issue.

 

gotcha...

also- that slight a difference could be the concentration of coolant... could be.