What is code po125 on a 2000 f150?

Answer 1

Code PO125: Insufficient coolant temp for closed loop fuel control.

This means that the voltage from the temperature sensor is lower than expected, and is being ignored. The fuel management system stays at default settings similar to a cold start. The oxygen sensor is not being used to adjust the fuel mix and the fuel mix will likely be on the rich side. Also, depending on the system, the intake air pre-heater may stay on.

Causes:

1. Coolant temperature too low, engine does not come up to temperature; Thermostat stuck open, or missing.

2. Temperature sensor failed.

If your engine appears to be warming up ok, then it is likely the temperature sensor. Typically, coolant temperature sensors may fail within 4 to 5 years.

Your engine may have 2 temperature sensors: one for the fan, and another for the fuel management system. Consult a repair manual.