P1544 code for 2007 mitsu galant

[subict2015]

Can anybody help me on this?
Engine light on for my 2007 Galant 4cylinder . . . .what's the possible cause. Any suggestions??
thanks

[Voodoo]

Moved to 9G Car Problems forum.

Is your car overheating?
http://engine-codes.com/p1544_mitsubishi.html

[oakrdrs187]

Code comes up as a coolant issue, low level maybe?

[subict2015]

Code comes up as a coolant issue, low level maybe?
The dealership has three possible hint: thermostat, Sensors & radiator cap.

I already changed my radiator cap for an original one since it's been a while (2007 model) . . ., but then i was still thinking if it was the thermostat . . .but the engine light went off for about a week (to my surprise), then yesterday afternoon the light went on again . . . .

I guess i'll try to have my engine coolant check . . .before I decided to buy & replace my thermostat for $300++ from the dealership . . . .

[subict2015]

Early 1st quarter of 2014 I already changed my timing belt at 105K mileage, & my water pump as well. . . . .they changed my engine coolant as well . . . .and after about 6 mths. that's the time when the engine light went ON . . . . .my engine has a 123K mileage as of now.