# Hazard light lighting up when Prius headlights, radio and heater are on.



## lenaitch (Feb 10, 2014)

I have no clue about EVs or hybrids, but spurious electrical problems can be maddening - and expensive - so good luck. Batteries do have a shelf life but I don't know how that can be assessed. Did the hazard flashers come on or just the lighted dash button? I ask, but have no clue what to do with your answer, but others might. It could be leakage or a short in the dash circuit board.


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## Nik333 (Mar 1, 2015)

Just the lighted triangle, but, it might have alarmed, too.


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## ukrkoz (Dec 31, 2010)

*DO NOT RUN OUT OF GAS!!!!!!!!!!!!!!!!!!!!!!!!*

*How to know when hybrid battery is failing
What causes hybrid batteries to degrade and fail?*

Eventually all batteries will fail. Hybrid Electric Vehicle (HEV) NiMh batteries have a life cycle. When the hybrid battery does not last as long as the rest of the vehicle, replacing it costs several thousand dollars and creates hazardous environmental waste. Delaying battery failure beyond the service life of the vehicle will reduce the negative environmental impact of hybrid vehicle ownership and save the vehicle owner thousands of dollars.
This graph depicts the typical life cycle of a Hybrid Electric Vehicle (HEV) hybrid battery:









There are three major phases of hybrid battery lifespan. Usable capacity and performance decreasing as the battery ages:
Typically begins: Typically ends: Phase 1: Healthy hybrid battery New Vehicle 3-6 years Phase 2: Weakened/weakening hybrid battery 3-6 years 5-11 years Phase 3: "Failed" hybrid battery (DTC code present) 5-11 years

Each hybrid battery 'pack' is comprised of many individual battery cells. Consumer hybrid electric vehicles have anywhere from 120 to 240 individual battery cells. Each cell is about the size of a typical D cell battery. At the beginning of the hybrid battery’s life, each cell easily provides all of the energy needed to propel the vehicle and to stay in sync with other cells in the battery pack. As time progresses, the battery will start to degrade and the cells will fall out of sync with each other. Results of this degradation include:
(1) usable cell capacity is reduced
(2) cells drift out of balance with each other (voltage delta).
The speed of this deterioration is determined by a variety of factors, including vehicle make/model, climate, driving habits, variation in battery cell construction, and more.
This battery deterioration means that the individual cells within the battery pack can have a different charge level and capacity - they are no longer 'in sync' with each other. Some cells can be 'full' while other cells in the same battery pack are 'empty'. The overall battery pack performance is limited by the vehicle's battery management system to the weakest cell when discharging and the strongest cell while charging. As a result, the wider the cell imbalance, the narrower the usable range of the hybrid battery becomes. The car's battery management system uses only a limited range of the battery cells actual physical capacity (80%-40% for Toyota and 80%-20% for Honda). As the usable capacity decreases and the cells become further and further out of balance with each other, the vehicle us able to use less and less of the batteries actual capacity. The vehicle cannot correct this imbalance problem on its own. The car cannot force the cells back into balance with each other.
If no attention is given to the hybrid battery, it will 'fail' and the check engine light/hybrid battery light will be illuminated.


*How do I know if my hybrid battery is failing?*





There are several subtle cues displayed by a hybrid vehicle that can alert you to degrading hybrid battery capacity & performance. If not acted upon, the battery will ultimately display a fault code for battery 'failure'. By paying attention to the warning signs and performing preventative care on the battery before it 'fails', you can easily improve battery health and prolong its life. Prolong Battery Systems will improve hybrid battery performance, save you thousands of dollars in avoided replacement hybrid battery costs, and benefit the environment by requiring one less hybrid battery to be manufactured. _(Note: The symptoms described below are applicable to Toyota vehicles. Honda vehicles display similar symptoms. Feel free to give us a call and we can describe the Honda symptoms for you.)_









The *first indication* of decreased battery performance is a reduction on fuel economy and diminished vehicle performance. The vehicle does not get the same fuel mileage that it used to and it feels sluggish - lacking in power during acceleration. If equipped, EV mode may be less frequent and for shorter duration then when the vehicle was newer. This happens because as the hybrid battery weakens, the vehicle is forced to use less of the battery and more of the gas engine. It also spends more time charging the hybrid battery in the background (i.e. not shown on the dash). Both of these behaviors reduce fuel economy. This can last for several months as the battery weakens and fuel economy/performance progressively decreases. Note: sometimes under inflated tires can cause similar symptoms. We recommend checking your tire pressure to be sure that is not the cause of decreased fuel economy.










The *second warning* that your hybrid battery is failing is called negative battery recalibrations. This is initially seen when parking the car for a few days (such as over a weekend) or when parking the vehicle overnight. Just before the vehicle is parked, the dash battery display shows a full or near full hybrid battery. When the car is started the next morning (or a few mornings later) the battery display shows an empty or near empty battery. The empty battery indication can be displayed immediately when the car is started or drop from full to empty in the first few minutes of operating the vehicle. This occurs most often in warmer climates or seasons, but as the battery degrades will happen in any climate. This is a clear sign of a weak battery that needs attention soon. If ignored, the battery will soon progress to the point of failure. If treated with Prolong Battery Systems before the battery degrades further, the success rate for recovering the pack and restoring it to good operating condition is nearly 100%.
The *third and final warning* the vehicle displays of a failing hybrid battery is negative recalibrations that occur while the vehicle is being operated. These recalibrations often occurs on warm days or when idling the vehicle for longer periods (such as waiting for a parking spot or railroad crossing), but as the battery weakens can happen at any time. These are seen as the dashboard battery charge display suddenly dropping from near full to near empty. This drop is followed by the gasoline engine revving to a higher than normal idle speed while force charging the battery from empty to full. This event is easily visible on the dashboard battery display and can be audibly heard by the loud, unusual high idling of the gasoline engine. This can be very unsettling behavior as the vehicle seems to ‘take over’ and ignore driver inputs while force re-charging the battery. *This is a red flag, serious battery issues are imminent.* In these cases, we strongly recommend using the Prolong Battery Reconditioning Package to perform a preventative battery reconditioning as soon as possible. Ignoring these symptoms for more than a few weeks will result in the battery displaying a failure code and being stranded on the side of the road. If treated with Prolong Battery Systems as soon as these symptoms become present, the success rate for recovering the pack and restoring it to good operating condition is nearly 90%.
The next phase of battery failure is a failure light on the dash and cell failure. Our products can still help vehicle owners in this situation, but the success rate depends on how long it has been since the failure first appeared. If this describes your car, please give us a call to discuss your specific situation and learn how much our products can help you and your hybrid vehicle battery.


https://hybridautomotive.com/pages/faq


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## Nik333 (Mar 1, 2015)

@ukrkoz - Thanks! Last night I made sure the radio, & heater were off when I started the car. It did fine. I will have to watch the battery display more often.

How much of the article was sales do you think? I am not very trusting of the Toyota dealership, here.


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## wrbrb (Aug 18, 2020)

Are you saying your fuel gauge no longer works, so you're relying on the icon of the hybrid battery charge level to alert you to a low fuel situation?

I had a 2012 Prius C and remember it saying in the owner's manual not to ever let it run out of gas, because if it does, you can't just add more gas on the side of the road - certain dealerships have special chargers to help get the battery charged again if it's been depleted to a certain level due to lack of fuel to help recharge it.


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## Nik333 (Mar 1, 2015)

wrbrb said:


> Are you saying your fuel gauge no longer works, so you're relying on the icon of the hybrid battery charge level to alert you to a low fuel situation?
> 
> I had a 2012 Prius C and remember it saying in the owner's manual not to ever let it run out of gas, because if it does, you can't just add more gas on the side of the road - certain dealerships have special chargers to help get the battery charged again if it's been depleted to a certain level due to lack of fuel to help recharge it.


My auto insurance said it happens a lot to new owners of Priuses because they overestimate how far it will go. There are actually three ways to tell when gas is low, but, it takes time to learn. It's always started right away with new gas.

If it required battery chargers for running out of gas, that would be a terrible car to have in a Wildfire Evacuation when there are long lines evacuating!


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## wrbrb (Aug 18, 2020)

What are the three ways?


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## Nik333 (Mar 1, 2015)

wrbrb said:


> What are the three ways?


The gas gauge, of course, the battery icon (?), not sure what to call it. Then miles left to drive after you fill up. I seem to have two gallons left when the cluster says zero miles left. So, after I fill up, it says, say 480 miles left. I guess it bases it on your MPG average. Once it hits zero, which you may never let it get to, fill it up & see how it compares to your total capacity. I think that was 12 gals total.. So, it says zero at 2 gal left.
There's a little gas pump pic near the number.

I only learned this because a small part of the cluster went out with a water spill. The dealership told me it would be $2000 a few years ago, to replace the cluster, without looking at it.. Later, I learned that there are three sections & the whole thing doesn't need to be replaced.

The only real downside to not having the gas gauge is safety. It is easier to glance at the gas gauge than hit a button to see the cluster. But, there are the controls on the steering wheel, too.


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## chandler48 (Jun 5, 2017)

Nik333 said:


> There is another way to tell the speed and the gas level.


Sure. I had a 1962 Volkswagen I drove to college in Mississippi. You could tell how much gas you had when it ran out. You just flipped a lever under the dash and you had a "reserve".. You made sure you returned the lever to the original position when you filled up, or the next time you ran out of gas, you would not have the reserve.

Speed.........just keep an eye out for the blue lights.


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## Nik333 (Mar 1, 2015)

chandler48 said:


> Sure. I had a 1962 Volkswagen I drove to college in Mississippi. You could tell how much gas you had when it ran out. You just flipped a lever under the dash and you had a "reserve".. You made sure you returned the lever to the original position when you filled up, or the next time you ran out of gas, you would not have the reserve.
> 
> Speed.........just keep an eye out for the blue lights.


A cop suggested I drive behind the semis which I do. I'd rather look at the scenery, anyway, than speed. There is another speedometer in there, also, for fast moments. I can feel when I'm going too fast, as a rule, but, it reads out the speed every few minutes, anyway.


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## Nik333 (Mar 1, 2015)

Maybe something is wrong with the heater? I had no trouble tonight but kept the heater off when I would restart it.


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## ukrkoz (Dec 31, 2010)

Nik333 said:


> @ukrkoz - Thanks! Last night I made sure the radio, & heater were off when I started the car. It did fine. I will have to watch the battery display more often.
> 
> How much of the article was sales do you think? I am not very trusting of the Toyota dealership, here.


You go to toyotanation Prius section and ask there. Your batteries are failing. Yes, some of that article is sale p itch but, consensus there is - pretty darn close to reality.


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## Nik333 (Mar 1, 2015)

"But, in general, a brand new Toyota hybrid battery replacement cost will run you between *$2,200* and *$4,100*. This does not include labor costs. A used battery will cost you upwards of $1,500, while a refurbished *Toyota Prius* battery will cost $1,500 or more. May 6, 2020"
Prius Battery Replacement Cost ? Is It Worth The Cost?

 😊 @ukrkoz - Hey, there's a guy with your name talking about the Prius battery at the forum!


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## lenaitch (Feb 10, 2014)

chandler48 said:


> Sure. I had a 1962 Volkswagen I drove to college in Mississippi. You could tell how much gas you had when it ran out. You just flipped a lever under the dash and you had a "reserve".. You made sure you returned the lever to the original position when you filled up, or the next time you ran out of gas, you would not have the reserve.
> 
> Speed.........just keep an eye out for the blue lights.


I remember those old VWs very well. If you were quick, you could flip it when the engine first stumbled and it would recover. I started motorcycling before bikes had gas gauges; you either kept your eye on the odometer or, when stopped, gave the tank a slosh. Most bikes only got away from the 'on/reserve' tap when they went to fuel injection. The comment about returning the lever to 'on' is very true. There is no greater sinking feeling when you in the boonies trying to make the next town and, when the engine stumbles, you reach down to flip it to 'reserve' and discover it is already there.


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## ukrkoz (Dec 31, 2010)

Nik333 said:


> "But, in general, a brand new Toyota hybrid battery replacement cost will run you between *$2,200* and *$4,100*. This does not include labor costs. A used battery will cost you upwards of $1,500, while a refurbished *Toyota Prius* battery will cost $1,500 or more. May 6, 2020"
> Prius Battery Replacement Cost ? Is It Worth The Cost?
> 
> 😊 @ukrkoz - Hey, there's a guy with your name talking about the Prius battery at the forum!


I'm super mod at toyotanation. Been in hybrid section for forgot how many years. That's the place to go to, if you have Prius questions. They talk Prius, not VW, you know.


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## Nik333 (Mar 1, 2015)

I don't mind their reminiscing. I had an older Karmann Ghia.


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## raylo32 (Nov 25, 2006)

Yup, this reserve setup was typical of motorcycles for a long time. My 1977 Honda 550 four had one... and I believe even my 1983 Honda Sabre had one even though it had a gas gauge. Current 2012 triumph Tiger with fuel injection does not have a reserve.

And speaking of reserves and getting that sinking feeling... reserves were a common thing back in the day for SCUBA diving... J-Valves with reserve and diving without a tank pressure gage. We would just dive until the air ran out, flip the lever and begin to mosey on back to the surface. One time mine failed at 100 feet down... flipped the lever and no more air! Luckily my buddy was closer to me than the surface and we buddy breathed back up.



lenaitch said:


> I remember those old VWs very well. If you were quick, you could flip it when the engine first stumbled and it would recover. I started motorcycling before bikes had gas gauges; you either kept your eye on the odometer or, when stopped, gave the tank a slosh. Most bikes only got away from the 'on/reserve' tap when they went to fuel injection. The comment about returning the lever to 'on' is very true. There is no greater sinking feeling when you in the boonies trying to make the next town and, when the engine stumbles, you reach down to flip it to 'reserve' and discover it is already there.


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## Nik333 (Mar 1, 2015)

raylo32 said:


> Yup, this reserve setup was typical of motorcycles for a long time. My 1977 Honda 550 four had one... and I believe even my 1983 Honda Sabre had one even though it had a gas gauge. Current 2012 triumph Tiger with fuel injection does not have a reserve.
> 
> And speaking of reserves and getting that sinking feeling... reserves were a common thing back in the day for SCUBA diving... J-Valves with reserve and diving without a tank pressure gage. We would just dive until the air ran out, flip the lever and begin to mosey on back to the surface. One time mine failed at 100 feet down... flipped the lever and no more air! Luckily my buddy was closer to me than the surface and we buddy breathed back up.


Funny, the comments reminded me of my dive boat. It had 2-22gal gas tanks. Unsinkable, too. Shoot. We should have gone to an outer island. . .


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## Nik333 (Mar 1, 2015)

Okay, tonight I did fine. No problems. I do idle a lot at night & that may have stressed the system, especially with the heater cranked up. California style, thin clothes,flip-flops, no coat. So I tried using the coat instead of cranking up the heater. What a novel idea! 🤣

Thanks ukrkoz, for all the options. I will pay more attention to the battery.


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## Nik333 (Mar 1, 2015)

I found this video which is kind of funny considering the way we look at things according to our experiences. I'm older than him and I was pretty used to running out of gas with my Pinto! ( Long trips from Calif to Nebraska and back)


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## raylo32 (Nov 25, 2006)

It is just crazy that some mfgs still have trouble with something as simple as a gas gage. KTM street motorcycles also have this kind of issue. And my Corvette... well not MY Corvette but some like mine... get stuck gas gages. This happens to some folks who park their cars for winter with a lot of gas in them. For some reason this causes the sender to stick. And that is like a $2000 job to fix due to labor. I don't store mine like that. I take it out and drive it almost anytime it is over 40 degrees and sunny.


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## Nik333 (Mar 1, 2015)

raylo32 said:


> It is just crazy that some mfgs still have trouble with something as simple as a gas gage. KTM street motorcycles also have this kind of issue. And my Corvette... well not MY Corvette but some like mine... get stuck gas gages. This happens to some folks who park their cars for winter with a lot of gas in them. For some reason this causes the sender to stick. And that is like a $2000 job to fix due to labor. I don't store mine like that. I take it out and drive it almost anytime it is over 40 degrees and sunny.


He has three ways to see how much gas is left, he just doesn't know it. I only know it because desperation made me more observant.

He has another video, apparently, about how the headlight wiring can be defective. I've taken my Prius to Mitsubishi twice now for a dimming light and will be going a third time. They didn't know this. But, at least I'm not afraid they will take me for an arm and a leg like the Toyota Dealership.


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