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Po116 ECT fault

L

Linebacker

New member
Hey so I've been having the code Po116 pop up almost every day for the last week. It's a soft code and doesn't trigger a ses light but my coolant temp needle drops to 0 and the fans run on high.

once I clear the code the temp gauge returns to normal and the fans stop. I've tried replacing the ECT sensor and I've checked all the wiring to the pcm but I'm still getting this code any ideas?

2005 gtp comp-g
 


t stat is cake, its two bolts. replace the t stat and the gasket. 15 minute job tops.

theres a rubber ring that fits around the lip of the t stat, if yours is torn up replace it too. its like a buck or so. gaskets like 2 bucks, t stats are about 10.

stock is 195 degree.
 
i forgot, those damn temp sensors are known to be bad brand new out the box. some guys have to get 2 or 3 of them till one works right.

may want to check if your heat seems to be less hot when the temp needle drops. it could be false due to the temps sensor still being bad.
 


Hey so i replaced the T-Stat and that was the issue. The gauge has worked fine since and no codes in over a month.

Next issue im having tho is when i replaced the T-Stat i noticed the coolant air bleeder valve had seized and was not working properly. I replaced it with a doorman one and it worked fine to bleed out the air but i notice that it leaks a trickle of coolant when the engine is hot. The threads came with a red seal on it already but is there something else i can use to maybe seal it up better?
 
I took out the bleeder screw and wrapped the threads in teflon tape and it still leaks out. its a very slow but steady stream..
 
Hey so this issue just popped up again.. i am guessing the most likely cause is the T-stat failed prematurely...i am thinking of just taking it to a shop Monday and getting a coolant flush and a new T-Stat.. what do you guys think
 


Like we said a long time ago, it could be the sensor itself. The code means a circut range/performance problem.

If the temp on the dash hasnt changed and you arent getting low heat, then the thermostat is likely the not the problem.
 
i have replaced the sensor twice. once at a shop and than i did again when you guys mentioned they can come faulty out of the box. the wiring has also been inspected by me and i also went to a shop that is specialized in wiring. i only think its the t-stat because that is what fixed it last time.

this issue is very aggravating
 
If you clear the code and it comes back within minutes, it's not going to be a thermostat itself. Because it's just a piece of metal with a spring.

Does this code come back right away or does it take a while when you drive it??

A P0128 is the more common failed thermostat code for sticking open.
 
Ya I can clear the code with the car running and the temp gauge will instantly return to normal and the fans will shut off. I have been trying to think of something im doing now that I have not done in the last 6 months that might be related and the only things that I can think of is

1. Its a lot colder out so that seems to be a common factor because last time this happened is was still cold out

2. I plug in my car... and last night I plugged in my car and than it happened this morning... but I cant think of any connection between plugging in my block heater and this fault.
 
Get a GM Ac delco sensor only. Do NOT get BWD, Delphi, or any other aftermarket but original DELCO GM. This WILL solve your prob 100%.
 


[h=2]"Code po116"[/h]
"Code po116 , temperature gauge stays on cold, both fans are running put 2 thermostats new. It probably needs a new coolant temp. sensor that's what the po116 stands for."
 
well the first temp sensor i am not sure what brand it was, The second one i ordered was from rockauto and was an AC delco. So get another one of those and try that?
 
Linebacker said:
well the first temp sensor i am not sure what brand it was, The second one i ordered was from rockauto and was an AC delco. So get another one of those and try that?
Click to expand...

Well you can try another Acdelco "from the dealer" so you can return it if it is bad, but in the event that the "dealer one" does the same thing, then I would look toward the harness or the PCM. I've seen delco pcms have a similar fault that it turns on the fans when it has an internal fault or short. But first after replacing with new a "dealer" sensor check and rule out the harness as not being bad then look into the pcm as being the prob with internal issues or pcm harness. By any chance did you jump this car recently for a bad battery or jump some body else's car or started it with a battery charger "START" mode. This can definitely hurt the PCM internally to cause issues like the fans turning on for no apparent reason and trip a code as well.
 
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