Insufficient Coolant Temperature for Closed Loop
Powertrain Code · Medium
What does P0125 mean?
The engine is not reaching operating temperature quickly enough for the ECM to enter closed-loop fuel control. Usually caused by a stuck-open thermostat.
System: Coolant System
P0125 is a powertrain diagnostic trouble code indicating insufficient coolant temperature for closed loop. This code is classified as medium severity, which means: schedule service — affects performance or emissions. We have vehicle-specific diagnostic data for 43 models below. Select your vehicle for tailored causes, symptoms, and repair cost estimates.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your vehicle.
See causes, symptoms, and repair costs for P0125 on specific vehicles: