Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control: Description
A thermistor is built into the Engine Coolant Temperature (ECT) sensor and changes the resistance value according to the engine coolant temperature.
The structure of the sensor and connection to the ECM is the same as the Intake Air Temperature (IAT) sensor.
HINT:
If the ECM detects the DTC P0115, P0117 or P0118, it operates the fail-safe function in which the ECT is assumed to be 80°C (176°F).
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0125 | Engine coolant temperature change is minimal for 96 seconds after engine start (2 trip detection logic) |
|
| P0125 | Engine coolant temperature change is minimal for 142 seconds after engine start (2 trip detection logic) |
|
| P0125 | Engine coolant temperature change is minimal for 20 minutes after engine start (2 trip detection logic) |
|
HINT:
Confirm the ECT using the intelligent tester. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
| Temperature Displayed | Malfunction |
|---|---|
| -40°C (-40°F) | Open circuit |
| 140°C (284°F) or more | Short circuit |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.