So today I was driving down the road and CEL came on my 06 Civic EX with AT and 198K(I believe T-stat is Original one), after scanning the code it's P0128.

Usually temperature gauge on the ODO shows 3-4 dots on the highway and they rise to halfway, once I am in stop and go traffic.

I was literally thinking about it, that there's possibly a problem with T-stat since it was brutally cold in last few days and car was usually showing 2-3 dots on highway, but NO CEL.

I think thermostat is stuck open and needs to be replaced, that's why a CEL. Anyone has any other ideas or advice? Don't plan to throw parts at it, but seems like T-stat is a good start? Or should I test ECT1 and ECT2 sensors first?

Thanks very much for your help and advice.

 

Do you have a scan tool that can read live data - if not a quick test of the ECT wouldn't hurt.

If you do go for the t-stat (which I would based upon the brief description), I suggest getting an OE for these types of things.

 

Thank PM, no I don't have a live scan tool.

How can I do it? Can a loaner tool from any of autoparts store would work?

Also, my first plan is to replace T-stat with an OEM one and then go on from there.

Planning to buy :
OR

https://www.ebay.com/itm/Genuine-OEM...!US!-1&vxp=mtr

Do you know any other place which could have a cheaper one?

Thanks again for the help.

 

By any chance, does anyone know if they both are same?

https://www.ebay.com/itm/Genuine-Hon...!US!-1&vxp=mtr

https://www.ebay.com/itm/Genuine-Hon...!US!-1&vxp=mtr

Because it looks like all dimensions and everything is same, I have one laying around from an older accord.

 

Has anyone here used Tama or Aisin thermostat and is it an OEM brand?

https://www.ebay.com/itm/Honda-Tama-...tUGiBJ&vxp=mtr


http://www.rockauto.com/en/moreinfo....588308&jsn=148


Thanks for all the help

 

It was T-stat, replaced with an OEM one and all is well

 

Glad to know the car is "happy" again