Hello, I am new to this site. I have honda accord 2007 2.4L had engine code P2183 previously. I have changed both ECT 1 and 2 (radiator ect1 and ect2 engine driver side.) Also replaced the Thermostat, radiator. Checked cooling pump. Car is no overheat, the temperature gauge reads only 1/4 of scale and scan code read 171oF even though I drove long on highway. Car heater is also OK.
Today I replaced the second time ECT 1 and 2 bought on RockAutoparts.com after replaced the second time ECT's, I drove on highway and engine code came back. I scanned it appeared code P1172 A/F sensor. As what i think the ECU thinks engine is still cold and pumps more gas that caused the P1172 on.
Want to fix the the cold ECT first....
Any help is greatly appreciated.
Today, I drove 36 miles to work with cold temperature in Boston. The upper radiator is hot but the lower radiator hose is cold. How come engine runs not hot enough for thermostat to open?
Before I took the thermostat out and they were hot for both upper and lower radiator hoses.

 

Any help?

 

The thermostat is connected to the lower radiator hose. If the lower radiator hose is still cold, the thermostat has not open. There also may be air pockets trapped in the cooling system if the thermostat did not open during the air bleeding process.

Also, did you use an OEM thermostat?