2004 Nissan Sentra P0128 Error Code: Thermostat or ECT Sensor Replacement?
What is the most likely solution for resolving the P0128 error code in a 2004 Nissan Sentra 1.8L GXE? Should I replace the thermostat or the Engine Coolant Temperature (ECT) sensor to fix this issue? Please advise based on technical recommendations and common repair practices.
I recommend starting with the thermostat replacement. Ensure you use a thermostat rated for the correct operating temperature—do not use a lower-rated unit. Testing requires removing the thermostat, so consider time, cost, and consumable factors before proceeding with replacement.