how to resolve P0128 code on my Tesla Outback 4th Generation (2010-2014)

Learn how to diagnose and fix P0128 cooling system issue in Subaru Outback (2010-2014). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

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

2. Inspect Coolant Level

• Sub-steps:
  • Open the hood and locate the coolant reservoir.
  • Check the coolant level; add a mixture of 50% coolant and 50% distilled water if low.
• Tools Required: None

3. Replace Engine Coolant Temperature Sensor (if faulty)

• Sub-steps:
  • Locate the ECT sensor, usually found near the thermostat housing.
  • Disconnect the wiring harness from the sensor.
  • Use a socket to remove the sensor from the engine block.
  • Install the new sensor and torque it to the manufacturer’s specification (usually around 12-15 ft-lbs).
  • Reconnect the wiring harness.
• Tools Required: Socket set, torque wrench
• Safety Warnings: Ensure the engine is cool before working on any engine components.

4. Replace Thermostat (if faulty)

• Sub-steps:
  • Drain the coolant from the radiator into a clean container.
  • Remove the upper radiator hose and any retaining clips or bolts to access the thermostat housing.
  • Remove the thermostat and gasket.
  • Install the new thermostat with a new gasket, ensuring it is oriented correctly.
  • Reattach the upper radiator hose and secure it.
  • Refill the cooling system with the correct coolant mixture.
• Tools Required: Socket set, screwdrivers, gasket scraper
• Safety Warnings: Always allow the engine to cool before draining coolant to avoid burns.

5. Clear Codes and Test Drive

• Use an OBD-II scanner to clear the P0128 code.
• Start the vehicle and allow it to reach normal operating temperature.
• Monitor the coolant temperature and check for any recurrence of the code.