How is this for strange?

[Ry' N Jen]

When I have used the block heater for three or more nights (when it is above zero degrees Celsius/32 degrees Fahrenheit),
the check engine light comes on and produces a P0116 Engine Coolant Temperature Circuit Performance trouble code.
But the DTC is not reproduced when I leave the block heater unplugged!

 

[rockymountain]

Maybe it means it doesn't need a block heater when it is above freezing.

 

[kb0nly]

Hmm thats odd.... But yeah i think Budke is right, it could just be the computer is expecting the coolant temp to be lower than it is?

 

[kj924]

Uhhhhm....sorry Ryan, but someone has to ask....Why do you plug it in if the temp is above freezing in the first place?

Like Budke said: it may be a result of too much heat. We had an emergency generator at the hospital I worked at,that had a problem with the block heater....the heater never shut off, keeping the coolant way too hot.

 

[hyde]

Why do you have to plug/unplug it? I have engine block heater but I never touch it. It is always plugged.

 

[RageOfFury]

Why do you have to plug/unplug it? I have engine block heater but I never touch it. It is always plugged.

Wow you must have the world's longest extension cordWow1.gif

 

[LibertyTC]

Ryan,
Are you leaving it on all night? If so it would be possible that the coolant is too warm.
I only block heat for 3 hours max in our temp when below freezing, so I can imagine how hot it is if left on for many hours.
Just try putting it on a timer or plug in 2 hours only if above freezing. See if that fixes it.

 

[LibertyTC]

After block heating,I forgot to ask, when you start it, what is the ****-trip reading for coolant temp?

 

[valvestem]

Another question to ask is what are the parameters for the Engine Coolant Temperature Sensor? On cold start of course.

 

[JeepKj03]

The computer uses multiple sensors to check if the sensors are working correct. The intake air temperature takes a reading and if there is a difference it will blow a code. I don't see why a block heater would be needed above 32F/0C. I'm curious what does your temperature gauge read when the vehicle is started.

 

[HoosierJeeper]

Mine starts fine in 22 degrees without a block heater. Maybe wait till it's below 0 degreeF...

 

[kj924]

Mine starts no problems in -35 C without the block heater...I never use a block heater.

 

[kb0nly]

Mine started fine all last week in subzero air temps, and even -40F wind chills were recorded for one of those days, -20 to -30 wind chill most of the week. Sure it cranked slow and i wished for a block heater to make it easier on it, but no cash for it right now.

 

[Luke]

(popcorn) *waits for Socks* *These guys are in for it* lol3.gif

 

[kj924]

Mine started fine all last week in subzero air temps, and even -40F wind chills were recorded for one of those days, -20 to -30 wind chill most of the week. Sure it cranked slow and i wished for a block heater to make it easier on it, but no cash for it right now.

Are you sure you don't have a block heater? Mine was still wrapped up and zip tied to the passengers side of the engine bay...I had to look hard to find the plug, but it was there.

 

[tjkj2002]

Mine started fine all last week in subzero air temps, and even -40F wind chills were recorded for one of those days, -20 to -30 wind chill most of the week. Sure it cranked slow and i wished for a block heater to make it easier on it, but no cash for it right now.

Windchill has zero effect on how your vehicle starts,if it's -10 degrees actual temp and -50 with windchill the engine is still only at -10 degrees.


My Kj has also started like a champ in temps at/around -30 degrees,no hint of slow cranking either but I use the correct weight of oil(5w-30) and have always had a massive CCA battery also.


As far as the engine code it was already stated the PCM is reading various sensors and is confused by the ECT sensor reading.basically having the block heater on at warmer temps and for to long makes the PCM think the t-stat is opening to early.

 

[kb0nly]

Are you sure you don't have a block heater? Mine was still wrapped up and zip tied to the passengers side of the engine bay...I had to look hard to find the plug, but it was there.

Yep, i've been up in there twice now, i can see the freeze plugs in the block, no heater...

 

[kb0nly]

Windchill has zero effect on how your vehicle starts,if it's -10 degrees actual temp and -50 with windchill the engine is still only at -10 degrees.


My Kj has also started like a champ in temps at/around -30 degrees,no hint of slow cranking either but I use the correct weight of oil(5w-30) and have always had a massive CCA battery also.


As far as the engine code it was already stated the PCM is reading various sensors and is confused by the ECT sensor reading.basically having the block heater on at warmer temps and for to long makes the PCM think the t-stat is opening to early.

Yes i know that... I wasn't implying that it affected the vehicle, i was just saying thats how cold it was to us human beings...

However the washer fluid in my wife's car, rated to -25F was starting to turn to slush so i had to quickly dilute it with isopropyl alcohol and then top off with Prestone washer fluid rated for much lower temps after i got some of it pumped out. That was my fault, i forgot to change out her washer fluid when it got cold, i run the cheap stuff in the summer and pump it out in the winter. So i know air temp wise we made it down there, of course my weather station here was also telling me the same thing on those days.

 

[Ry' N Jen]

Hey guys,

First off, the only time I use the block heater is when it was below zero Celsius.
It doesn't even need it as the engine fires up just fine without it.
I just used it because it heats the engine up faster than without the block heater
plugged in.
Based on that, I used it for a few more days and thats when the code occurred.
Then as an experiment, I left it unplugged for the next week and the DTC
disappeared.
I then plugged it in again for the next 3-4 days to see if I could replicate the DTC,
which it did.
I figured that the PCM was confused that the coolant was warm without
the engine being run and that, that is why the P0116 code.

I posted this as I thought that this might be of interest for everybody here.

Tim, never thought to check the ****-trip!

 

[HoosierJeeper]

Did the code go away once you started driving?