Hi guys,

Yes, i did a search but couldn't come up with much help...all i found were posts about what the p0128 code is.

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

As soon as I got a description of the code, I knew what the problem was: my aftermarket Mishimoto thermostat. I recently installed the thermostat with the matching fan switch and aftermarket radiator cap.

the aftermarket thermostat's job is to operate at a lower temp than the stock thermostat, hence the CEL.

My question is what could I do to not get the code anymore (besides putting the stock thermostat back in)?

i currently have the following installed: AEM V2 intake, headers, exhaust, thermostat, fan switch, and radiator cap.

thanks guys!

 

If you know what the problem is and you want the code cleared, just bring it to an Autozone. The one near me usually clears them for me...they always tell me they're not supposed to do it but that doesn't always stop them

 

Did you able to resolve that P0128 CEL issue ?
I have the stock thermostat & sensor & this thing popped up twice already before I reset it again. The Temperature bars in the dashboard has never past 3 bars. Still Could not figure out.. Any pointers are appreciated.. thanks

 

I have a J's thermostat, my car does the same thing. If you let it warm up full bars the light won't come one I have thought about switching to Spoon as its operating temp is a few degrees higher which might prevent this. Whats the operating temp of the mishimoto??

 

60 degrees which is super cool compared to stock..

 

you can get a radiator cap with less pounds of pressure to increase coolants boiling point. it should get rid of CEL, but yeah it defeats the purpose of the thermostat opening at a cooler temp.