how to fix P0128 code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather tools and parts required for repair.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Thermostat

• Tools Required: Socket set, torque wrench, coolant catch pan.
• Sub-steps:
  1. Drain the coolant into a catch pan by opening the radiator drain plug.
  2. Remove the engine cover if applicable.
  3. Locate the thermostat housing and remove the bolts using the socket set.
  4. Carefully separate the thermostat housing from the engine and remove the old thermostat.
  5. Clean the mating surfaces on the housing and engine to ensure a proper seal.
  6. Install the new thermostat, ensuring proper orientation.
  7. Reattach the thermostat housing and torque the bolts to the manufacturer's specifications (typically around 10-15 ft-lbs).
  8. Refill the cooling system with the correct type of coolant as specified in the owner's manual.

3. Inspect and Replace Coolant Temperature Sensor

• Tools Required: Socket set, multimeter.
• Sub-steps:
  1. Locate the coolant temperature sensor, typically found near the thermostat housing.
  2. Disconnect the electrical connector from the sensor.
  3. Remove the sensor using the socket set.
  4. Install the new sensor, ensuring it is tightened securely.
  5. Reconnect the electrical connector.