What does the P0128 code mean for a Ford?

I’ve been having a problem with my car’s check engine light coming on. I found out it was a P0128 code. But there’s nothing wrong that I can see. The first time it happened, I reset the battery, and the light went away. But about a month later, it came back. I went to a mechanic, and they said it was a minor thermostat issue (P0128 code). The light turned off when he checked it with his computer, but now, a month later, it’s on again. I don’t notice any issues with the car. What should I do?

The P0128 code for a Ford means the engine coolant temperature is lower than the thermostat’s intended range. This indicates that the Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected the engine is running cooler than expected. This could be due to a faulty thermostat or a problem with the coolant temperature sensor.

The mechanic’s diagnosis of a minor thermostat issue might be correct, it’s possible that the underlying problem is more complex.

Try looking out for this issues as well

  1. Use a thermometer to check the coolant temperature when the engine is running. If it’s not reaching the optimal operating temperature, it could be a sign of a thermostat issue.
  2. Inspect the coolant hoses and radiator for any signs of leaks.
  3. If the problem persists, it might be worth visiting a mechanic who specializes in diagnosing electrical issues. They can use advanced diagnostic tools to pinpoint the exact cause of the P0128 code.