So ive got the code P0128 a half a dozen times in the past month or so. Can anyone tell me why? it only happens when im comming home from work not in the mornings when the car has set all night. i live in nor cal andits been mid 50s to high 60s outsideo its not like its cold. and i usually give my car a bit to warm up but its still poping up. coolant is full. any ideas? btw the code says "coolant temp is lower than the rmostat can regulate".

 

engine is running to cold, replace your t stat..

 

Ok,thought that could be it. thats something that will be covered under my warantee, correct?