CEL came on. Troubleshot by feeling upper rad hose while engine warmed up. Swapped t-stat and now it remains cool until engine is at temp. This also resulted in the dash gauge going up to just before mid range, whereas before the swap it only went up a quarter at most under heavy highway driving.

My question now is what to do about the CEL that still remains. I've given it about a week to self-reset but it has not. Do I clear the code and see if it returns or assume the ECT sensor/sender is malfunctioning and replace that?

Thanks guys.

 

Bueller? Bueller?

 

What are you using to clear the code?

It takes about 20 run cycles for a code to reset. I have one of the bluetooth ODBII plugs and the app Torque on my phone. It will tell me the engine coolant temp as well as the temp of some of the other components.

I would reset the code and monitor the temp with the Torque app to see what was actually happening.

 

I haven't tried to clear the code with anything yet. I have a U480 CAN OBDII Memoscan that can will clear it but it doesn't have any fancy bluetooth capabilities or real time scanning as far as I know.

If I can find one that does, what would I be looking for that the temp gauge isn't?

 

The temp gauge is a glorified idiot light. I suggest you clear the code and see if it comes back.

 

2009 ranger 4.0l SOHC engine right?
Always good to include that in first post


Thermostat was stuck open which is why you got P0128-coolant temp too low after warm up

You needed to install a 192-195deg Thermostat, stock temp, if they sold you a 180deg then you will need to change it.

Yes, on the 2009 the computer runs the dash temp gauge, but not quite an idiot light, oil pressure gauge is, lol.
Your temp gauge should run at 1/2 or just below, that would be "normal" temp after warm up, 190-200deg
Pulling a heavy load or climbing a long uphill grade running just above 1/2 would be normal.

temp gauge at a 1/4 is costing you money in MPG and shortens engine life.
Faster it gets to 1/2 the better, for engine and your wallet

Stop by auto parts store and ask them to read and clear the codes, if your reader can't clear that code

 

Yes, my apologies. 2009 4.0l SOHC engine. I got a stock thermostat from the dealer for too much money bht based on where the temp gauge is now sitting after the engine warms up, the new t-stat is working great. Just below 1/2.

Sounds like this code won't go away on its own and I should manually clear it. I didn't want to clear something that isn't fixed but it sounds like if it isn't fixed, the code will return and I could proceed from there.

Thanks guys (or girls)