SidCivic

Hi Everyone,

My 21 day old 2015 Honda Civic LX's low temperature sensor (blue light) comes on 2-4x a day upon starting and stays on for approx. 3 minutes. Half the time it stays on for only 30-60 seconds. It never comes on while driving; only when starting the car from parked position. It occurs after starting from overnight, and even from starting after being stopped only for 2-3 hours. It occurs after the car has been out on the street, and parked in our garage. I bought the car on 5/29/15. It did NOT occur for the first 2 weeks, but happens daily in the last week. I live in San Diego where the temperature has hovered from 64-78 degrees during the time of this problem.

1) What problems could be causing the light to come on and stay on?
2) If it's normal like some people say, then why did it not happen for the first 2 weeks after I bought the car?
3) Wouldn't it display from day 1 if it's so normal? Also, wouldn't it have displayed on the dealer lot when I first test drove it b/c that would be a much more likely situation when the engine was cold and needed to get up to temperature?

Sorry if this question has been answered elsewhere. Please link me to that thread and I'll post there. Any help you can give is appreciated, and thanks!

- Worried New Civic Owner

ezone

Read your owners manual!

It's normal. It's supposed to come on. It goes out when the coolant temp inside the engine rises above ....something like 110-120 degrees F. (I don't remember the exact number)

If your area is rather warm, especially in bright sunlight, the underhood temperature may be high enough to keep the blue light off.

In the middle of winter I wait until the blue light goes off, then I turn on the fan for my heater.

SidCivic

Hi Ezone,

I did read the owner's manual. It says the light may come on for a few seconds. Mine stays on for 3-4 minutes (timed) 2x a day. How long does your light stay on? Is it safe for me to turn on the heater or AC while the blue light is on when I am parked? Let me know, and thank you.

ezone

Erm, not quite. Read it again.

From your owners manual:

● Comes on for a few seconds when
you turn the ignition switch to ON (II),
then goes off.

(This is a 'bulb check', most of the other lights also come on for about 2 seconds at the same time. This happens when you simply turn the key on without starting the engine.)
(Also, I didn't copy the footnote about pushbutton start cars here. ON (II) would be pushing the start button twice without your foot on the brake pedal.)

● Comes on when the engine coolant
temperature is low.
(This is where you are at now.)

● If the indicator stays on after the engine
has reached normal operating
temperature, there may be problem
with the temperature sensors. Have
your vehicle inspected by a dealer

-------------------------------------
It varies directly with ambient temperature, temperature of the liquid inside the engine, and how much fuel I can get it to burn after startup. Simple Physics.

Mine might be out by the time I reach the end of the parking lot at work in the middle of summer @ 95-100+ degrees out.



The colder it is, the longer it takes to get the engine warmed up and turn the blue light off. Could be a minute at 90+ degrees outside, could be much much longer if it gets real cold.

In the winter here it gets ....... zero to -5* F, occasionally maybe 10 below zero F...If I remote start the car and it only idles for 10 minutes, that blue light is still on when I get in at the 10 minute mark.
If I jump in and start driving immediately when it's that cold, it takes a little less time to get the light out. Maybe 2--2.5 miles into my commute (stop and go).
If I could jump right onto the interstate immediately after starting, it would go out much quicker.

More work = burning more gas = more heat quicker.
You can heat up a gallon of water with a bic lighter, it's gonna take a long time. You could use a blowtorch and speed it up.

Sure. If you NEED heat, there won't be much available until after the blue light goes out though. Even at that moment, there still may not be a lot of heat but at least you won't get a blast of ice cold air.

Make more sense yet?
The blue and red temperature lights took the place of a real temperature gauge, and that's about it.

HTH

SidCivic

Hi EZone,

Thanks for taking the time to give me a detailed reply! Yes, everything you're saying made sense. It always made sense, but I guess I just didn't think my 3 week old Honda would need 3 minutes to get to optimal running temp after overnight during a 65 degree San Diego summer. Based on your response and others, it IS normal and it just DOES take that long so I am relieved now. Thanks again!

CraigW

iTrader: (1)

It is not at optimal temps in 3 mins..... but is warm enough to switch off the cold light.

My 2010 leaves the very 1st segment nearest C on at cold start, this must also be a cold warning method utilized.

SidCivic

Thanks for the info Craig!

miss_annette

Hi I just got a 2015 Civic and my coolant light does the same. Stays on but as soon as I drive it turns off. I'm glad to know its normal. I was almost going to call the dealer.

Mikeyyy

My scanguage shows 125 F coolant temp when the low temp light goes off.

2012 civic Lx

yes i know old thread!

ezone

I finally got an Ultragauge, I think mine shows 127.x F when my blue light turns off.

CraigW

iTrader: (1)

That is when I turn the heat on, once it extinguishes.