the sensor would not make it run cold it would only give a false reading if it was faulty, running cold is either the thermostat is stuck open or the fan is doing major overtime.
P0128 Engine Running too cold?
- Thread starter Dusty_GMT800
- Start date
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Dusty_GMT800
Full Access Member
I meant that if the sensor was faulty would it cause my Engine Temp Gauge to read too low or just never go up at all? As of now it sits below 185 when reading the gauge in my dash, but during the last week when the weather was warmer I didn't really have an issue. Only seems to happen on cold days which is why I'm leaning towards it being the thermostat stuck open.
your gauge should always read the same temp unless its really hot out and your idling or your towing or driving it pretty hard it may go up a little then, but it shouldn't be cooler unless the engine was just started and it hasn't got up to normal temp yet, but again the sensor would only give a bad reading it wouldn't actually make the motor run cold it's just a sensor its doesn't do anything other than give you information.
Dusty_GMT800
Full Access Member
Gotcha, on my way to work there was a decent amount of traffic before the highway, the truck warmed up to about 185 before I got on the highway according to the gauge. However, in the morning I got onto the highway without much traffic and the truck never reached the normal operating temperature. Just curious, the normal operating temp is 185 correct?
But if the sensor is faulty it could cause the engine to believe it is running too cold is that what you are saying? Does seem like the engine is actually running too cold sometimes since when the coolant temp on the dash is below 185, the heat is not as hot, however, when it is up to normal operating temperature the heat blows hot.
But if the sensor is faulty it could cause the engine to believe it is running too cold is that what you are saying? Does seem like the engine is actually running too cold sometimes since when the coolant temp on the dash is below 185, the heat is not as hot, however, when it is up to normal operating temperature the heat blows hot.
Well that's why I suggested feeling the heater, unless you want to try and trouble shoot the sensor that's the second best way to tell, if the temp says low and the heater is not as hot then it's likely the thermostat
Dusty_GMT800
Full Access Member
Heater definitely feels warm when the truck is actually warmed up, my new thermostat and housing comes in Wednesday (thank you amazon prime) How involved is the coolant sensor change? I may as well just change it out for a new one if I am already going to drain and flush the radiator anyway.
should be in location #6 or in the same vicinity
eh that's a pretty crappy photo, its here
M1Gunner
Full Access Member
You would know if the ect sensor was bad. The signal to the pcm would read -40 and the truck would be extremely hard to start if at all considering how rich the fuel trim would go.
Engine running too cold... stuck open thermostat.
Engine running too cold... stuck open thermostat.
Dusty_GMT800
Full Access Member
Got it, so looking at the other picture you sent it's on the passenger side under the plugs. Shouldn't be too hard to replace if I have to do it.
Well it starts up just fine, so I guess it's the thermostat, new one comes in today, hopefully I have a chance to do it sometime this weekend.
