2002 Ford Explorer XLT, 79K miles, automatic, P0125 - Insufficient Coolant Temp For Closed Loop Fuel Control
Truck idles a little rough when stopped (whether in drive or neutral gear). I suspect this is because the truck is running in "Open Loop Fuel Control" mode, which is probably too rich.
Parts store printout says the most likely cause is a bad thermostat, and that's all it says. But my engine temperature gauge comes to 40% (4/10ths of the way between C and H) in the normal amount of time, like it always has, and the heater works fine, as always. Could it be the coolant temperature sensor instead? If so, wouldn't that cause the engine temperature gauge not to read normally?
Should I replace the coolant temperature sensor, the thermostat, or both, or could it be something else? Thanks in advance for any advice.
Sensor:
hook it up to a meter and drop it in some boiling hot water.
Thermostat:
https://www.youtube.com/watch?v=-1uszG_4B54
Or if it's not that expensive, save time and just replace it.
Thanks MMJ. Yeah, if I have to pull them out to test them anyway, I might as well just replace them both. I think the two of them together wouldn't even cost $40.00.
The thing that bothers me the most is that my dashboard temp gauge is acting exactly like it always has...
Yeah, I disconnected the battery and cleared the code. If it comes back, then it's either the ECT sensor or the thermostat. Coolant level is optimal. Thanks for the link!
Replace both, just for quality. The thermostat may be stuck open and the sending unit may be corroded.
If the thermostat was stuck open, would the temperature gauge get to normal operating level in the usual amount of time?
Maybe, maybe not. Depends on a lot of other factors.
OK, thanks Doc.