how to fix the P0128 code on my Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool down completely before starting work.

2. Replace Thermostat

• Tools Required: Socket set, torque wrench, coolant catch pan, gasket scraper.
• Drain the coolant from the radiator using a catch pan.
• Remove the thermostat housing bolts with the socket set.
• Carefully lift the thermostat housing to access the thermostat.
• Remove the old thermostat and clean the mating surfaces with a gasket scraper.
• Install the new thermostat in the correct orientation (check for orientation marks).
• Reattach the thermostat housing and torque bolts to the manufacturer’s specifications.

3. Replace Coolant Temperature Sensor (if necessary)

• Tools Required: Socket set, multimeter, wiring harness cleaner.
• Disconnect the wiring harness from the coolant temperature sensor.
• Remove the sensor using the socket set.
• Install the new coolant temperature sensor, ensuring it is securely fastened.
• Reconnect the wiring harness and clean any corrosion with a wiring harness cleaner.

4. Refill Coolant

• Refill the cooling system with the manufacturer-recommended coolant.
• Start the engine and allow it to reach operating temperature, checking for leaks during the process.

5. Reset Check Engine Light

• Use the OBD-II scanner to clear the P0128 code from the system.