P0126 Coolant Temp Insufficient

[Batmobile_Engage]

As far as I know, the engine coolant temperature sensor must see a certain operating temperature
(I'm guessing about 160 degrees) in a specified amount of time following startup. If the coolant fails
to reach this temperature after X-amount of minutes, P0126 CEL appears.

A few people have suggested that the thermostat is frozen open, coolant needs to be changed, etc.

About 11-1/2 months ago, my factory themostat was frozen CLOSED so I ordered and installed a Grimmspeed
thermostat which was rated at 168 degrees and added brand new mixed coolant (I think the factory one
is 174). I did notice lower coolant temps. while highway driving in the cold, winter months. No issues
though...until now.

Yesterday was the second time I've thrown this code in 3 weeks. The first time, I thought it was just a hiccup,
read the code and reset the ECU with my Cobb AP. (When this code activates, the car defaults to fail safe
mode. Solid CEL lamp and flashing CRUISE lamp.)

Any ideas?

 

[Spamby]

Change thermostat back to factory spec and see what happens. Either that or investigate the CTS... coolant sensor

 

[Batmobile_Engage]

Ugggh....if this keeps happening, that's what I'm going to have to do I think. :-(
I would need to get a new factory thermostat though. My old one was so severely
seized shut, that it only opened after pounding on it with a 5 lb. mallet and punch
for a few minutes. Obviously, I threw it out.

I've been trying to find info on the CTS, but haven't seen much yet. I briefly wondered
if it would be possible to have Holy tweak the tune, ecu parameters, whatever....to move
the temperature threshold value down a few degrees. Just a thought.

Lastly, I'm wondering if my coolant itself could be a problem. I used 50/50 mix when I filled
it, and later when I worked an air bubble out and topped it off, I used water (long story).
I wonder if the mixture being off could cause this. Like I said, it's not everyday. It seems to
be sort of random, but definitely has a lot to do with starting the car and travelling at high speed
in the winter before coolant temps hit normal operating range.

 

[HolyCrapItsFast]

I think Spamby is correct.... I use to throw these codes when I had the lower temp thermostat. The issue stopped when I reinstalled the stock stat.

There really should never be a reason to go with a cooler thermostat because the engines of today are engineered to operate at those temps and are most efficient at those temps. The factory thermostat is 195*. If your car is running to hot then you should consider an after market radiator, not change the thermostat. With cooler thermostats, you run the risk of oil sludge accumulation during winter months because the engine never really gets to its operating temp and moisture builds. You also run the risk of OBDII emissions component failures because these components are looking for proper operating temperatures.

Ugggh....if this keeps happening, that's what I'm going to have to do I think. :-(
I would need to get a new factory thermostat though. My old one was so severely
seized shut, that it only opened after pounding on it with a 5 lb. mallet and punch
for a few minutes. Obviously, I threw it out.

I've been trying to find info on the CTS, but haven't seen much yet. I briefly wondered
if it would be possible to have Holy tweak the tune, ecu parameters, whatever....to move
the temperature threshold value down a few degrees. Just a thought.

Lastly, I'm wondering if my coolant itself could be a problem. I used 50/50 mix when I filled
it, and later when I worked an air bubble out and topped it off, I used water (long story).
I wonder if the mixture being off could cause this. Like I said, it's not everyday. It seems to
be sort of random, but definitely has a lot to do with starting the car and travelling at high speed
in the winter before coolant temps hit normal operating range.

 

[Batmobile_Engage]

Damn....... Thanks guys :doh: