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.
Inspection Procedure
HINT:
- If DTCs P0115, P0116, P0117, P0118 and P0125 are output simultaneously, an ECT sensor circuit may be open or shorted. Perform the TROUBLESHOOTING OF DTC P0115, P0117 OR P0118 FIRST .
- Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
- CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0125)
Result
RESULT CHARTDisplay (DTC output) Proceed to P0125 A P0125 and other DTCs B HINT:
If any other codes besides P0125 are output, perform the troubleshooting for those codes first.
B: GO TO RELEVANT DTC CHART
A: Go to next step
- INSPECT THERMOSTAT
- Check the valve opening temperature of the thermostat.
OK:
Valve opening temperature is 80 to 84°C (176 to 183°F)
HINT:
Also check that the valve is completely closed below the opening temperature shown above.
NG: REPLACE THERMOSTAT
OK: Go to next step
- Check the valve opening temperature of the thermostat.
- CHECK COOLING SYSTEM
- Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or a modified cooling system.
NG: REPAIR OR REPLACE COOLING SYSTEM
OK: REPLACE ENGINE COOLANT TEMPERATURE SENSOR
Use the Manual With the Right Hardware
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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.
