how to fix the P0128 code in my Ram 1500 DT (2019-Present)

Learn how to diagnose and fix P0128 code in Ram 1500 DT. Step-by-step guide with diagnostic procedures and repair instructions for cooling system issues.

Solution

1. Preparation

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

2. Inspect and Replace Thermostat

• Tools Required: Socket set, torque wrench, gasket scraper.
• Remove the engine cover (if applicable) using a socket set.
• Locate the thermostat housing and remove the bolts using a socket.
• Carefully remove the thermostat housing and the old thermostat. Note the orientation of the thermostat for reinstallation.
• Clean the mating surfaces of the thermostat housing and engine block with a gasket scraper.
• Install the new thermostat in the correct orientation and replace the thermostat housing.
• Torque the housing bolts to manufacturer specifications (typically around 15-20 ft-lbs).

3. Replace Engine Coolant Temperature Sensor (if needed)

• Tools Required: Socket set, multimeter.
• Locate the ECT sensor, usually found near the thermostat or on the engine block.
• Disconnect the electrical connector from the ECT sensor.
• Use a socket to remove the ECT sensor from the engine.
• Install the new ECT sensor, ensuring it is securely fastened.
• Reconnect the electrical connector.

4. Refill Coolant

• Open the radiator cap and refill the cooling system with the appropriate coolant mixture as specified in the owner's manual.
• Start the engine and allow it to reach operating temperature while checking for leaks around the thermostat housing and ECT sensor.

5. Reconnect Battery

• Reconnect the negative battery terminal.