Ls5speed

Hey guys. Traveling over the weekend and my check engine light came on. Today, I went to autozone and had them scan it and turns out it is P0128 meaning coolant is below normal temp. They suggested replacing the thermostat, but as I drive my coolant is between 180-190 degrees, which is what it has always been. Can anyone help me out?

Sharkey

iTrader: (1)

p0128 sets when it detects the car took longer to warm up than it expected. the ecm is programmed to know roughly how long it should take to warm up, the idea behind it is so you know when your thermostat has gone bad. the problem is its not at all accurate. gm had a reflash for this code setting and nothing else being wrong. way back when i first bought my car it would set the code on mornings when it was very cold. gm reflashed it when doing some recalls, no more issue.

basicly if you car warms up and doesnt drop below 180 once its warm, the thermostat is good and you can ignore the code

tomj77

iTrader: (2)

or your coolant temp sensor is bad, mine kept tripping and I changed it and it stopped

Ls5speed

Ok thanks... it's weird because now it went away randomly so maybe it was just a one time thing.

Sharkey

iTrader: (1)

if your coolant temp sensor is bad your wont have an engine temp reading on the dash, and a code p0118, coolant temp sensor open circuit.

bahoodle

its the thermostat eventually if u dont change it ur coolant temperature will say --- that code goes away if u get the engine warmed up quickly by driving like a dick i waited a year to change mine but yea if it cuts out durin winter ur heater will work like **** heres a vid for it on a 2.2 if u wanted some instructions lol https://www.youtube.com/watch?v=psTA5Ach_tI