BATTERY COLD LIGHT

It's an indicator that your available power will be reduced, so you don't pull out too close in front of the gravel truck and get in trouble. Adjust your driving accordingly and all will be well.

Mike

The "battery caution light"? You mean, in addition to the yellow snowflake-plus-exclamation-point that comes on when the outside temp goes below 37 degrees?

This is the first that I've heard of a 2005 Prius (NHW20) having a "battery caution light" coming on due to cold weather...

On a Classic Prius (2001-2003) NHW11, there are 2 engine coolant lights on the dash. They both look like a thermometer on wavy "water" lines. Blue = cold coolant, red = hot coolant.

I have not heard of the red hot coolant light coming on (other than the brief time at startup when all the other lights come on and off in self-check), even on cars driven through Death Valley. If this is the light coming on, you should visit your dealer.

However, the blue cold coolant light is perfectly normal to come on and stay on when you first start the car, and stay on for the first 5-15min of driving (depending on the outside temperature). The light says that the engine coolant isn't up to proper operating temperature (the engine coolant is cold, to be expected if the car has been sitting undriven for a while), so the engine will probably be running (and not at its most efficient state) to warm the coolant up (among other engine/emissions components). Don't expect your MPG to be much higher than about 30MPG for the first 5min segment of your driving, as the engine will be running (and not going into electric). It is perfectly safe/fine to drive with the blue cold coolant light on, but just try not to overly stress the engine (floor the accelerator, go up a very steep/long hill, etc...)

Some 2001 Prius may even show the orange turtle light on some very cold/windy days, indicating that the hybrid battery is too cold and will not be providing much/any power. (Acceleration will be a little sluggish (but still driveable - I didn't really notice the difference until after the turtle light went out), which is OK as you shouldn't be stressing the engine with the turtle light anyways...) Keep the heater on (and the back window shelf clear, where the battery vents are), and drive gently, and the light will go out in about 20min of travel (in my experience using backroads with my 2001, anyways; I don't know timing for pure highway driving).

On the 2004-current Prius NHW20, the blue cold coolant light has been removed from the dashboard, as has the Turtle light. (On North American models, the Prius also now has the Coolant Heat Storage System (CHSS), a pump and a specially-designed thermos-like container that stores some of the warm coolant when you turn off the car, and then returns the warm coolant when you start the car, to help shorten the car's warmup period.) However, there is a new icon - an orange/yellow snowflake on a perspective road symbol, which indicates that the outside temperature is below 3C/37F (that roads may start to freeze/ice over). This flashes on the MFD and then stays next to the outside temperature reading. On the 2004-2005 models, it also appears on the dashboard and stays there (scaring many new owners when the weather gets cold), but was removed from the dash starting in 2006. This icon, sometimes called "Flakey" by owners, is even listed as a safety feature in some countries...

Richard,

I was referring to the small "snow flake" looking symbol. Your explaination makes a lot of sense. Thanks all!

Asa

richard schumacher wrote:

OK, so what is "Flakey" trying to tell me to do? It showed up during my trip to Yellowstone National Park and we couldn't figure out from the owner's manual what to do in response.

I think it's just warning you that the roads may be icy. Poeple don't always think about the possibility of black ice etc when they set off for work on a cold morning, so it's not a bad idea to remind them that they may need to moderate their driving style when it's close to freezing outside.

Paul

The yellow snowflake is telling you that it is colder than 3C/37F outside. At this temperature, black ice may start forming on the roads, particularly bridges/overpasses or some shady areas by the side of the road. (Ever see "bridge freezes before road" signs before?) "Flakey" is just there to remind you to drive cautiously as it is cold enough outside for ice to start forming on the roads.

So why doesn't every Toyota, or for that matter every car on the road, have this new indicator light. They all suffer the same control problems on black ice, don't they? Is there not something unique about the Prius that instigated the creation of this indicator?

It's warning you to drive carefully because there may be patches of ice on the road. It's nothing at all to do with the car itself.

Wellll... the anti-wheel-slip system is kinda aggressive, in that it doesn't take much slippage to engage it; it has to do this to prevent damage to drive system components. Consider the snowflake a reminder to drive with a light foot so that you don't get surprised when the anti-slip system kicks in. One practical effect is that you need to give yourself more time/distance from oncoming traffic to get up to speed from a standing start.

At the same time, a damp or slightly gravelly road will do the same thing and there is no warning about those conditions.

Many cars that have an outside temperature display will also warn of ice conditions.

For example:

Saab 9000

VW Passat Mazdas with the autodimming mirror: And there are some aftermarket products that warn if outside temperatures could lead to black ice:

PNI Wayfinder:

Roadpro: Gentex NVS Auto-Dimming rear-view mirror:

Considering that Toyota has considered the Prius to be a platform for introducing new technology (for examples see the hybrid system, auto-park (IPA), and the Smart key system), it would not be surprising that the Prius may have a feature that other Toyotas do not have yet... But the "outside temperatures cold enough that ice may form warning light" is not a Toyota-specific new technology.

My '06 Avalon gives a warning "May be Icy?"

Thank you, I was not aware of these other implementations.