My car is throwing a P0128 check engine code. It is coolant temp below regulated. I have changed my thermostat and made sure I had full and good coolant. Not sure what else I can do. The car fan comes on pretty quick and keeps the car cool. I don't know if there is a alter temp thermostat I can get to stop this code or what.

 

what temperature thermostat did you install? was the problem occurring before you changed the thermostat? does your fun run for a little while after you turn the engine off?

 

I got a 180 degree thermostat and yea it was happening before I changed the thermostat. that is what I thought the problem was when I got the code first. Also my fan does run for a little bit after I turn the car off.

 

your fan controller is dead...this causes the fan to run constantly, even when your driving, which normally would turn the fan off, as air moving through the radiator while driving is sufficient to maintain normal operating temperature. Also your coolant temperature sensor could be faulty.

 

I agree with Crans on this one.... Had this problem with an 04 es. I would go with the temp sensor first that was my issue.

Defective Engine Thermostat
Defective Engine Coolant Temperature Sensor
Defective Intake Air Temperature Sensor
Defective Cooling System
Low Engine Coolant
Dirty Engine Coolant, causing incorrect Coolant Temperature Sensor readings
Defective, always running Engine Cooling fan(s)

Flush the system, change the Coolant Temp Sensor, clean your MAF "seems unrelated but your IAT sensor is there" check the fan controller for proper operation.

 

alright I will check into all that this weekend. thanks

 

would either of you guys know the OEM part numbers for the fan control and coolant temp sensor?

 

just for kicks, can you let the car idle for like 10 minutes, and take a picture of the temp gauge in the cluster?


part number for fan controller is in the part number sticky, but since I don't think the coolant temp sensor is in their, and it only takes two minutes to pull them up in ASA:


1355A124 - fan controller (very simple remove and replace...if you did your own thermostat, this will be a piece of cake...


MD177572 - water temp sensor (in the head, below the camshaft end housing...the one pin/quick disconnect looking thing on the thermostat housing is the sending unit for the gauge.

 

added the temp sensor into the sticky

 

thanks for the part numbers and I think I attached a pic of the temp gauge. The temp in the picture is about as hot as it gets all day even from driving it only gets a little higher.

 

if you cant see the picture of my gauge cluster I uploaded it to my garage photo album. since I apparently don't know how to upload pictures in the post. sorry

 

That is quite odd. Usually it should end up just under halfway. Check into replacing the fan controller and go from there.

 

I started looking into the fan controller now that I have the oem part number. thanks cranswick and raikiri.

 

yeah don't bother with the temp sensor, it looks like it's actually lower than normal...if i didn't know any better, i would still say the thermostat is stuck open...i mean even if the fan is running all the time, i would think it would still get a little hotter.

 

perhaps he got the wrong thermostat?