[cmm47172]

P0128
Got it once before, cleared it and it came back about a month later. Temp is running normal as usual. No issues that I can detect other than the CEL coming on.

Are you saying that I can clear the light and then after 4 warm up cycles the code will be out of the memory unless it see trouble and the light comes back on?

 

[Stevenitrosublette]

coolant temperature (ECT) sensor.....
Here is what it " May " be . If you vehicle is coming up to temp as normal and your not running low on coolant or you cooling fan is running all the time .... which world bring engine temp down ... but you say it runs temp Guage normally... them it's more then likely the coolant temperature sensor.

 

[Stevenitrosublette]

Also could be IAT sensor ? But I'd think you'd get two codes for that. One you have and one showing a IAT problem code .

 

[cmm47172]

can the sensor be replaced without losing any coolant? Where is it located? How can it be tested? Can it be tested while still installed?

 

[Stevenitrosublette]

I'm sure it can be tested ...... at the dealer who has Star scan. I'll look tonight where it's located

 

[cmm47172]

Back on December 30th, I decided to clear the P0128 code to see if it would come back. It stayed off since then but it's back today. I'm also seeing a p0300 code. Does anyone know what the p0300 is referring t? Also the car seems to be cooling fine according to the gauge. Can anyone tell me how to test the coolant sensor?

 

[Par5]

P0300 is a code for random misfire. I have this code and it’s giving me hell trying to fix it. I did have the ECT code but cleared it but I think it the temp sensor may be bad because I can get the truck to fire and run. If I shut I’d off and try to start it again it will not start unless I have my foot on the accelerator pedal.

 

[Par5]

I've run into a similar problem a couple times on my trucks. In both cases it was a bad ECT (engine coolant temp sensor). If the sensor is bad, the connector crudded up inside, or a damaged wire the computer will think the engine is colder than it actually is and will tell the injectors to provide more fuel than needed. Result is essentially flooding . That's why opening the throttle helps it start, you're letting in air to help alleviate the flooding