P0128 engine code

[gnelson13]

Does anyone know what service engine code 'P0128' means? The code reader says thermostat or coolant below threshold. My coolant level is good and I don't think I have a thermostat problem because my temperature gage holds steady. I have cleared the code, but get it back in a few days. Any ideas?

 

[ExplorerDMB]

We have a great Computer section (especially the EEC-V -- which is what your truck is). I went ahead and moved it there. Its under the Underhood and Driveline section

Anyhow, visit here: http://www.explorerforum.com/forums/showthread.php?t=147880

That should help you find the code and should hopefully point you in the right direction.

-Drew

 

[ExplorerDMB]

I found this:

P0128 - Coolant Thermostat (coolant Temp Below Thermostat Regulating Temperature)

-Drew

 

[gnelson13]

Dtc P0128

Thanks, Drew. I've Googled the code and found it listed lots of places, but not one of them suggests what I do about it. Thermostats are cheap enough that I can replace it to see if that fixes it, but I don't think that's the problem. The vehicle never overheats and the temperature gage stays right in the operating range. Do you know if there is a temperature sensor somewhere in the system that might be faulty and triggering the DTC? I checked the link you provided, but didn't see anything about the P0128 code.