Temperature Reading VS. Actual Temperature
January 8th, 2018, 11:27 AM
#1
CF Senior Member
Thread Starter
Temperature Reading VS. Actual Temperature
We just went through a extremely cold weekend setting new record lows all over in our area. We woke up Sunday morning with a low of -16F. Our 2014 Impala 2LTZ sat out in the driveway all night exposed to this bone-jarring cold, last running at about 7:30 PM the night before. When I got out of the house Sunday morning about 9:15 or so, it had "warmed up" to -15F. I did not attempt to start the car with the remote as I wanted to hear how it would react while cranking in this cold-soak condition. It did start with no problems, although the cranking speed was very slow. I was surprised to see when it did fire up and I had it running for less than a minute at -15F, that when I used the instrument display panel to display the temperature is showed +32 F, with the outside temp being an actual -15 F.
Where is the temp for the instrument panel display derived from? At this point, I see a difference of 47 F between outside temps and what the display showed. There were now DTCs displayed for incorrect temp circuits. When hot, the instrument panel displayed 181F.
Thanks,
Where is the temp for the instrument panel display derived from? At this point, I see a difference of 47 F between outside temps and what the display showed. There were now DTCs displayed for incorrect temp circuits. When hot, the instrument panel displayed 181F.
Thanks,
January 8th, 2018, 11:37 AM
#2
are you referring to the engine coolant temp or ambient temp sensor? the ambient temp sensor is not always a live reading. it updates based on computer programming. the update details are in the factory service manual. If has updated and is reading correctly now, your ok.
January 8th, 2018, 11:57 AM
#3
CF Senior Member
Thread Starter
Tech2, I assume the reading I am referring to is the ETC and is located on the instrument panel right over the steering column. The ambient temperate appeared to be pretty close and is located on the center stack where the radio display is located.
BTW - what is the lowest coolant temp that could be displayed -40 F? I was expect in to see something in the vicinity of -15 F when I started it Sunday morning.
BTW - what is the lowest coolant temp that could be displayed -40 F? I was expect in to see something in the vicinity of -15 F when I started it Sunday morning.
January 9th, 2018, 9:37 PM
#4
probably -40*C is the lowest reading.
when you unplug the sensor it defaults to -40*C. ...any thing below 0.5v or over 4.8 v the computer sees this as a fault.
i don't find it unusual that the fluid temp are a little warmer that the air temps overnight. My truck reads the same when i view the temp sensors with a scan tool before start up. takes a long time to cool 15liters of 100*C when its surronded by a 100*C metal heat sink.
i monitor the temp sensors so i can find the ideal block heater plug in time.
when you unplug the sensor it defaults to -40*C. ...any thing below 0.5v or over 4.8 v the computer sees this as a fault.
i don't find it unusual that the fluid temp are a little warmer that the air temps overnight. My truck reads the same when i view the temp sensors with a scan tool before start up. takes a long time to cool 15liters of 100*C when its surronded by a 100*C metal heat sink.
i monitor the temp sensors so i can find the ideal block heater plug in time.