2005 Chevy Equinox cooling issues

"the servicing was low, so I serviced it back up"

What does that mean? The code indicates the coolant isn't getting up to normal temperature in a certain amount of time. You might also be getting air from the heater that isn't as hot as normal. This would indicate a thermostat that is opening too soon or is stuck open.

When the engine isn't hot enough, fuel vaporizes poorly so some of it doesn't burn in the engine. This increases emissions and decreases fuel mileage.

To check this yourself, start the engine when it is cool and remove the radiator cap. Stick a thermometer in the coolant to measure its temperature when it starts to circulate. It should be around 190 degrees. If it is significantly lower, pinch the upper radiator hose for a minute, then see if the temperature goes up when you release the hose. If it does, suspect the thermostat.

If the coolant is already above 190 degrees, suspect the coolant temperature sensor.

Caradiodoc

Nope, lack of a radiator cap makes it impossible to measure the coolant temperature. What you can do is feel the upper radiator hose when the engine is warmed up, but that won't be very accurate. The hose should be too hot to hold onto for very long.

Your mechanic can connect a hand-held computer, called a scanner, to view sensor values. That will allow him to see what the coolant temperature sensor is reading and why it is setting that code.

Caradiodoc

caradiodoc