Inspection Procedure

HINT:

• If any of DTCs P0115, P0116, P0117 or P0118 are set simultaneously with DTC P0125, the Engine Coolant Temperature (ECT) sensor may have an open or a short circuit. Troubleshoot those DTCs first.

• Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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 ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0125)

Result

(a) Connect the intelligent tester to the DLC3.

(b) Turn the ignition switch ON.

(d) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

Result

Display (DTC Output)

Proceed To

P0125

A

P0125 and other DTCs

If any DTCs other than P0125 are output, troubleshoot those DTCs first.

GO TO DTC CHART

INSPECT THERMOSTAT

(a) Remove the thermostat (see page CO-15).

(b) Check the valve opening temperature of the thermostat. Standard value:

HINT:

In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.

(c) Reinstall the thermostat (see page CO-15).

REPLACE THERMOSTAT

CHECK COOLING SYSTEM

(a) Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or any modifications.

REPAIR OR REPLACE COOLING SYSTEM

REPLACE ENGINE COOLANT TEMPERATURE SENSOR

DTC

P0128

Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

HINT:

This DTC relates to the thermostat.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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