bradb

Od thing happened on the way home from work. I fired the car up, drove out onto the street and by the time I went 1/2 mile the "Check Coolant Level" warning came on my DIC.

Outside temp was 92F. Water temp read 200. I pulled over and looked at the tank... half full. Called OnStark and got a negative. Fired the car up and no more warning.

Anyone go through this before?

TrackNoob

Hmmm....

Mileage on car?
Put any more miles on since then, with no codes or warning?

First I have heard of this happening, but with this newfangled level-sensor-free way of trying to extrapolate the coolant level from temp profiles...

I'd be sure your fan engages, be sure nothing is blocked in front of radiator, and if no further codes, just motor on.

We will chalk it up as an ideopathic pseudo-ischemic transitory temperature event (IPITTE - "I pity").

I suggest Lowenbrau, BID, and call back in the morning!

Zymurgy

This happened twice to me in the first 100 miles. Nothing since.

bradb

Thanks, Noob... 6500 miles.
Fans work and I didn't suck up a plastic bag.

I, too, think it is just some wackiness at work.

I've sucked down a couple of drams of Laphroaig and will just drive it again tomorrow... thank God for warrantys.

I suggest Lowenbrau, BID, and call back in the morning!

TrackNoob

Only info I had at hand that might be useful was from 'another forum':

The 2005 Chevrolet Corvette utilizes an algorithm-based low coolant level system which eliminates the need for the coolant level sensor previously positioned inside the surge tank (fig. 12).

The algorithm (a mathematical calculation) measures the difference in engine coolant temperature readings over time as a function of engine speed, to determine if the cooling system has a low coolant condition. After vehicle start-up, the ECM sends an engine RPM and engine coolant message through the BCM to the HVAC control head. The HVAC control head uses engine coolant temperature and engine RPM to determine if an increase in coolant temperature is due to a low coolant level condition.

This system is capable of losing 2 full liters of coolant before triggering the Low Coolant warning message. Because the surge tank holds approximately 0.8 liters when filled to the proper level, it's possible that a Low Coolant warning message is not triggered, even though the surge tank is completely dry.

TIP: After filling a system that has triggered the Low Coolant indicator message, the ignition must be cycled to turn the Low Coolant indicator off.

Diagnostic Tips
In the event that the Low Coolant message is present and the coolant is not low, verify that the RPM and Coolant Data (GMLAN) sent to the BCM matches the RPM and Coolant Data (Class 2) sent to the HVAC control module. If the RPM and Coolant GMLAN and Class 2 Data do match, the HVAC Module software needs updated. If the RPM and Coolant GMLAN and Class 2 Data do not match, the ECM and BCM software need updated.

TIP: This assumes that there are no RPM or Coolant codes set and no other messages or symptoms are present.

mwar99

Had it happen to me once with probably about 2,000 miles on the car. At a stop light when I accelerated the warning came on. Went away when turned off and back on again at next light. Nothing since.

bradb

THANKS!

That is what I needed to see. I'll have the stealer check that next time I am in... assuming they comprehend it... <laughing>

TrackNoob

I forgot to come back and post -- this actually happened to me on Thursday AM.

Background: I usually start the car, then plug in my phone, put it into console, arrange my bag and stuff on pass side... by the time I slowly pull out into my street, then main street, the car is fully up to 200-ish. Have had no issues at all for 7 months and over 10K miles.

Incident: Thursday, I had an early meeting, but left the house without time to spare. I just wheeled right out and into traffic. By the time I had traveled to my first traffic light (maybe 1.5 miles) the DIC told me "Check Coolant Level". I did not panic, because the guage was right at 210 where it usually is (these things run warm). I pulled over at the next station, where I usually get my paper and coffee, anyway. I popped the hood. I did not open the reservoir cap, but did note that the tank was completely full, engine compartment had no steam or excessive heat, no bad smell. I was very confident that when I got underway, things would be fine. Sure enough, DIC has not had another message, temp is right where it should be, and I watched it like a hawk since then.

Analysis: It seems clear to me that some combination of operating the car that involves faster than expected temp rise can lead the algorithm to falsely believe that it has detected a low coolant condition. I guess that on a crazy system like this with no true float or other level detector, that I would trade a false positive or two for a false negative, any day! In fact, it is possible that the rapid temp rise profile that triggers this is not good for the engine, and since this thing heats up to operating temp very quickly, it should be no problem to avoid it.


If my theory is correct, those who experience spurious "Low Coolant Warning" are *not* hot re-starting, but are probably starting cold, and that further, they are on the initial heat rise to operating zone -- that it does not occur spontaneously during regular highway conditions. I'd be interested to hear anything that either supports or shoots this idea down.

Abomination

happened to me too with about 100 miles on the car, then went away to never return. Never did have low coolant

ZO6Gal

I've got an '06 and it stays on all the time. The dealer told me that it was something to do with the pcm and to ignore it until they get an update for my VIN. I just hit the trip button and keep going. Good luck with yours.

TrackNoob

When you say 'all the time', do you mean as soon as you start the car, and each and every time you start and drive the car? And you are also saying that the 'trip' button resets the DIC message without stopping the car and restarting it?

:

blkvette1

These cars just do "crazy" things sometimes. The other day I pulled mine into the garage and shut it off. When the car shut down (lights, etc. off), the damn fog lights came on for about 5 seconds.

Could you imagine driving down the road, hitting the accelerator and the engine goes dead (this will be the case when "displacement on demand" reads a foul code and subtracts 4 cylinders when all you have running is 4 cylinders).

Technology is great (I am a programmer - 20 years) however; EVERY technological advance out there is in some sort of "beta" sequence. They might call it "release V3.5" but that is right next to "beta release V3.5" - the customer/client does the final checking and finds the problems. The Technology Dept. will then fix the problem ("beta release V3.51") and BREAK SOMETHING ELSE. This is the cycle my friends.

Welcome to technology.

ZO6Gal

Yes, it comes on as soon as I start the car. I usually just push the trip button so I can see the odometer. It will generally come back on in a matter of a few miles and I keep hitting the trip button to go back to the odometer. At first, I was mystified because my coolant temp was always perfect. I have taken it in for it but the tech told me he had no idea why it keeps coming back on. Anyway, maybe they will figure it out before too long. I have learned to ignore it I guess.