Error code P0128

[Paul Burroughs]

My 04 just poped a check engine light and I was able to pull P0128 Coolant Thermostat (coolant Temp Below Thermostat Regulating Temperature). The truck will not rev past 3k and when taking it for a drive it seems louder than usual in the cab with the windows rolled up. Anybody else have and fixed this problem?



Thanks in advance

 

[Kevin Palmer]

When you say it won't rev past 3000 RPM, are you doing the revving in Park or Neutral?

If so, then you are correct, it will not go over 3 grand as it has a safety limiter built into the ECM...

 

[Paul Burroughs]

Ah, I did't not know that interesting fact. I went ahead and replaced the thermostat and cursed the Ford engineers who designed the setup while in the process. Would it have killed them to add two inches of wire to the alt wire and route it under the intake?

 

[Todd Z]

It could have also been the sensor and not the T-stat.....



Todd Z

 

[Kevin Palmer]

Financially, 2 inches of wire times oh,,, lets say 3 million sales... It MAY have financially wiped them out.. LOL

 

[Paul Burroughs]

I took the cheaper of the two options of what could have failed. They seemed a little proud of the sensor at $22.00 for aftermarket. For that kinda of money I will go OEM.