Ive got a 2000 F150 with 59k on the clock. The service engine light came on and I took it to Autozone and they turned up a code 125 - insufficient coolant temperature for closed loop fuel control. I understand the closed/open loop operation just not enough to know how the coolant temp got thrown into the mix.

So does anyone have an idea what sensor this might be? Or where to look for the solution to the code? Its great that I was able to get the code but doesnt do me any good if they cant tell me what the problem is.

Thanks for the help.

 

Basicly, your engine is not warming up enough to go into closed loop (accoring to your engine coolant temp sensor). Possible causes are.
1. Low engine coolant level.
2. Faulty thermostat. (stuck open)
3. Fautly ECT sensor (engine coolant temp sensor)

If you are running a cooler thermostat, that would cause it to set also.

Best course of action.
1. Check your coolant level, fill if ness.
2. Replace the thermostat, use a "super stat' from Stant
it should be a 195 degree one.

Let us know how it works out.

Shawn

 

Thanks Shawn. Is the stat located at the end of the upper hose in the block? Looks easy enough to get to. This baby is bone stock, and Im eyeing a 04 SC at the dealer, so I dont really want to spend any more time and money than I have to, but Id be nice not to have the light on when I tade it in. Hell, I never even bought a manual.

 

Yep, engine side of the upper hose. Real easy to do, but be carefull when tighning it back up, you dont want to break the t-stat housing.