Key battery repeatedly low - one day after being replaced. Brand new car battery too. HELP!!!

[jje239]

My Auris hybrid told me the key Battery was low and with no warning it stopped working pretty much immediately. I called a breakdown company who replaced the key Battery and also told me my car Battery was low. So I called RAC and had a new car battery put it. RAC also told me the key battery was duff, even though it had only been put in the day before. 3 days later the low key battery sign was on again, so called RAC again who put another key battery in yesterday. Today the low key battery light is on again.

One other thing that may or may not be related is that the car alarm light is flashing doubly fast.

 

Please help!!!

[furtula]

Replacing the Battery in the key for is a pretty easy job, could be, but highly unlikely, that they used old worn out batteries (they get depleted over time).

Have you tried using the spare key, does it have the same issue?

For the blinking lights, turn hazards on, and check if all lights are working fine.

If one light dies, the other one will blink 2x as fast.

[jje239]

Thanks furtula,

The spare key is out of Battery! (genuinely, I think) and we couldn't get that replaced over the New Year period, but will try that today. 

I'd hope that it's unlikely that more than one repair company would give me a worn out Battery. Also, RAC man tested the car Battery he put it and said it was full. Will try the hazard light trick...odd thing is that before we had this key issue, I don't think the alarm light ever flashed, even on a slow speed.

 

[Rosgoe]

I had a 1998 rav 4 and the remote Battery went flat in a couple of days even with a brand new Battery turned out there was a dead short in the remote and basically was U/S .

as to the spare remote Battery being flat you can put the key into battery saving mode by pressing and holding the lock button then pressing the unlock button twice led will flash 4 times confirming this. When you say the alarm light flashing doubly fast do you mean the red led on the dash with the lock symbol this will flash slowly when the car is locked it will flash fast if you press the button by the interior light this is to disable the intrusion sensor if for example you lock the car with a dog inside.

I would also have the car scanned for any fault codes.

[jje239]

Thanks Rosgoe, I'm going to try putting a new Battery in the spare key and see what happens next...

 

[Parts-King]

If you can get a decent brand Battery, then do so, some of these cheap "no brand" batteries are useless. I often have to change them for customers who buy a card of 10 off auction sites for a pound and wonder why they don't work for long. The keys don't often fail, it's usually the battery 

[jje239]

These were all put in by mechanics. 3 failed batteries in less than a week - is that expected? Is it better to buy my own?

 

[Parts-King]

But were they 3 x Who flung dung makes? Try a decent Sony/Panasonic/Duracell Battery. They are only 3V and cheap things might have sat around for ages. Very rarely is the key faulty, not saying it isnt but far cheaper to try a decent make battery 

[jje239]

Agreed Parts-King, and thanks for your help. Will give it a go. Do you know whether there should be any connection between key Battery problems and the car Battery? Or is it pure coincidence that both should go at exactly the same time?

[TonyHSD]

27 minutes ago, jje239 said:

Agreed Parts-King, and thanks for your help. Will give it a go. Do you know whether there should be any connection between key battery problems and the car battery? Or is it pure coincidence that both should go at exactly the same time?

Hi, don’t know if there is pure connection between the car 12v Battery and the key fob been dead at the same time, perhaps if the car has not been in use daily that can cause flat batteries for both car and key, sometimes even brand new key batteries may not even work immediately after replacement if they had been on the shelf for a long time or poor quality as mentioned. There are some forum members that understands batteries well and once been explained here that if a li-ion batteries are not used in extended period of time may develop a condition that does not deliver power as required even though they have a good voltage readings. Best to try with new fresh stock and see how it’s going. Key fobs ate usually very well made and can withstand a lots of abuse including washing or swimming with them in a pool 👌 I usually buy Energiser made in Japan from Amazon and they last me over 12 months. 👍 if your car key has the same type CR1632 as mine this here is a good choice. 

https://www.amazon.co.uk/Energizer-CR1632-3V-Lithium-Batteries/dp/B004289YE4/ref=sr_1_4?crid=1OSS7OU4Z34WY&keywords=cr1632+battery&qid=1641387199&sprefix=Cr1632%2Caps%2C182&sr=8-4 

[flash22]

What type of fob do you have as some use a CR1632, CR1620 or CR2032 - as above batteries do expire and over time

when you get in the car and turn the car on, does the key light stay solid or flash in a pattern - if it flashes i means the key system has an error

 

[Parts-King]

43 minutes ago, jje239 said:

Agreed Parts-King, and thanks for your help. Will give it a go. Do you know whether there should be any connection between key battery problems and the car battery? Or is it pure coincidence that both should go at exactly the same time?

Coincidence I would say, they normally last a couple of years if a decent battery 

[Chriss27]

I went to Toyota dealer last month for new Battery and they gave me a Varta one for £5 then a few days later noticed Hone Bargains sell the same brand 

[flash22]

Page. 500-502

https://d24bc9lyrt5en5.cloudfront.net/Customer-Portal-Admin/emanuals/TOYOTA/OM12G98E.pdf

 

The smart key should have a CR2032

[jje239]

Yes its the 2032 I think. Warning light is solid, not flashing. Hopefully a new decent Battery will solve the issue. The strangest thing, and yet another coincidence I expect, our other car, which is a fully electric ZOE is also now showing low key Battery...

[Anthony Poli]

Where did you get the batteries from?

The ones from Toyota are ever so slightly thicker and have worked, When I have tried batteries sourced from other suppliers they seem to be unreliable or just don't work.

With having a service plan they were free. 

[Madasafish]

If you leave your key within 10 meters of the car, the key may try to connect .. and flatten its Battery.

[jje239]

@Anthony Poli - batteries were supplied by mechanics. The original came from Timpsons. 

@Madasafish - that is very interesting as our car is not parked too far from our house, so that could be a factor...

 

[Catlover]

Button batteries for key fobs are common to purchase, our local supermarket sell a wide range ie Duracell, Energiser etc. Keep away from cheap ones..... there is a saying "buy cheap, buy twice". Varta are another good make. You do need to know the number on the button Battery. They are very easy to replace, no need calling in mechanics, it it not rocket science to replace one. The expiry date is usually printed on the bubble card the Battery comes with, should be a good life ie now should be 2026 or more. Usually in 2'sor 4's.in a pack. That sorts the button Battery out.                                              

 

[Stivino]

1 hour ago, Anthony Poli said:

The ones from Toyota are ever so slightly thicker

Absolute tosh, they are all the same thickness as denoted by its part number. i.e. 2016 = 1.6mm thick.  2032 = 3.2mm thick etc.

[Stivino]

I have found that batteries from GP batteries have the most power (I’ve read all the data sheets) and the longest dates.

And, because they are Duracell, Energizer or any of the other big names, they are favourably priced.

[Anthony Poli]

46 minutes ago, Stivino said:

Absolute tosh, they are all the same thickness as denoted by its part number. i.e. 2016 = 1.6mm thick.  2032 = 3.2mm thick etc.

You are mistaken, the panasonic ones that I got from work were loose inside the holder.

[TonyHSD]

2 hours ago, jje239 said:

Yes its the 2032 I think. Warning light is solid, not flashing. Hopefully a new decent battery will solve the issue. The strangest thing, and yet another coincidence I expect, our other car, which is a fully electric ZOE is also now showing low key battery...

Perhaps the cold weather has some impact on batteries, I am expecting more 12v Battery, key fob batteries etc issues to pop up soon on the forum. I keep my key fobs in a cola can when the car is not in use to stop any signals going from and to the keys, stops thieves also from taking your car from your driveway, not that anyone would like to have mine 🤣👌

[Stivino]

51 minutes ago, Anthony Poli said:

You are mistaken, the panasonic ones that I got from work were loose inside the holder.

I'm not mistaken, that is how those batteries are nominated.  I suggest it is you who had made the mistake of maybe not having the correct Battery? i.e. putting a 2016 in the place of a 2032?

[Cyker]

My Mk4's Smartkey uses a CR2450!!   It looks massive compared to a 2032! Like a 2032 that had too many xmas pies