"Key Battery Low"

[Damer]

Is this essential, will it stop the car if the key Battery fails?

[Brian R]

If it is anything like my key, then yes, it is essential. From memory when mine showed the same warning it wouldn't start but in fairness only after I had ignored the "warning" for some time.

It's a dead easy process to replace the Battery and will take all of 2 minutes to complete. Plenty of key specific videos on Utube to give you the confidence to diy or of course approach your dealer.

[Las Palmas]

Short answer: No!

Longer answer: Change Battery, 2 minutes.

[scudney]

Just change it,simples lol 😆 

[AlwaysEddie]

No!

You can still use your car. But you will need to use the metal key in the fob to lock and unlock. To start the car when the Battery is dead, you need to hold the fob next to the stop/start button, then it will let you switch it on. Mind you, the car will be drivable but there will be all sorts of warnings, namely key not being detected, etc...

It's dead easy to change the Battery though, and you can switch off smart entry / remote start, etc from the dash, and buy yourself a Faraday pouch for your keys.  

[Damer]

Thanks all. I can get a Battery replaced. It was just that Wife is using car and I didn't want the "Key not detected" to turn off the car on her way home.

[Rabbers]

Strangest thing, but the only time I have had the KEY Battery LOW message was, rather alarmingly, upon starting an IS300h immediately after I had just changed the Battery.  I then restarted the car and, to my relief, saw  the message disappear after a few seconds never to be seen again.

 I habitually buy the CR2032  battery (which also suits my house gate controller) in a x4 or x6 economy pack and tend to replace it, I admit probably unnecessarily, every 20K km or so “just in case”.

[Moleman]

27 minutes ago, Rabbers said:

 I habitually buy the CR2032  battery (which also suits my house gate controller) in a x4 or x6 economy pack and tend to replace it, I admit probably unnecessarily, every 20K km or so “just in case”.

Just be careful about the size of Battery, my CT uses a CR1632.

[Rabbers]

58 minutes ago, Moleman said:

Just be careful about the size of battery, my CT uses a CR1632.

Sorry for any confusion that might arise from my mention of the Battery size for the RC (and other models) in the mistaken belief that all Lexus keys take the same.  

[Las Palmas]

27 minutes ago, Rabbers said:

Sorry for any confusion that might arise from my mention of the battery size for the RC (and other models) in the mistaken belief that all Lexus keys take the same.  

Fat car fat Battery.

Maurice is right, slim Battery for a tiny car.

[Rabbers]

1 hour ago, Las Palmas said:

Fat car fat battery.

Maurice is right, slim battery for a tiny car.

No question about it.  Privately I’ve always dreamed of employing a chauffeur (or perhaps a chauffeuse) to relieve me of the strain of carrying a fat key for my fat car around with me.

[Poundy]

Probably my only gripe about the ct200h is the silly screws located in the Battery retaining cover.

Use the wrong screwdriver and round the heads off at your peril. Both my keys had previously suffered the same fate, resulting in at least one of the corners being broken off to gain access to the Battery.

Removing the screws with a suitable extractor and repairing the broken corner was the easy bit but trying to match the replacement screws is a whole different ball game  😆

And no, Lexus don't supply.

 

 

[Damer]

4 hours ago, Poundy said:

Probably my only gripe about the ct200h is the silly screws located in the battery retaining cover.

Use the wrong screwdriver and round the heads off at your peril. Both my keys had previously suffered the same fate, resulting in at least one of the corners being broken off to gain access to the battery.

Removing the screws with a suitable extractor and repairing the broken corner was the easy bit but trying to match the replacement screws is a whole different ball game  😆

And no, Lexus don't supply.

 

 

Took it to local Timpsons they said they didn't want to touch it in case they broke the housing. Need time to take it to main dealer.

A bit annoying they only serviced the car a year a few months ago.

[Moleman]

5 minutes ago, Damer said:

Took it to local Timpsons they said they didn't want to touch it in case they broke the housing. Need time to take it to main dealer.

A bit annoying they only serviced the car a year a few months ago.

It is a two minute job, remove the key, slide the cover off, undo the four screws, replace the Battery, reverse the process.

[Rabbers]

Despite being the sort of person who gets nervous about the mere thought of using tools like a screwdriver or a hammer or sometimes even a corkscrew, I’ve never had the slightest trouble changing Lexus key batteries.  But now, after following this thread, I’m seriously worried my next attempt will end in disaster 😳 !!!

[Moleman]

10 minutes ago, Rabbers said:

sometimes even a corkscrew, 

Nothing should ever stop you using a corkscrew!!!  🤣

[Rabbers]

28 minutes ago, Moleman said:

Nothing should ever stop you using a corkscrew!!!  🤣

I didn’t say it stopped me! 

[Las Palmas]

Long ago I learned that correct good tools is half the work. 😇

[Rabbers]

16 minutes ago, Las Palmas said:

Long ago I learned that correct good tools is half the work. 😇

Unless you’re the sort of bad workman that blames them anyway.

[Poundy]

I used to do ground up Mercedes V8 restorations including complete engine and FI diagnostic/rebuilds.

My other hobby was making fast motorcycles lose weight and go faster, I have tools a plenty 🙂

But believe me there is no bigger PITA than a Ct200ch key fob that has had the screw heads rounded and a corner or 2 butchered on the plastic Battery retaining cover, unless of course you are not averse to buying a new fob. 😂🤣🤣

I had to fabricate/glue the plastic covers these are the closest screws available I could find from a previous thread...............

The required screw size is 1.6mm thread diameter, 3mm thread length with a head diameter of 3mm and a head depth of only 0.9mm.

The only ones close to that my searches / enquires came up with were 3 correct dimensions but a pan head with a head depth of 1.42mm in SS. What's half a mill me thinks, sod all, but alas it was too much to allow the fob cover to slide back on. I got round it by sanding inside the fob cover to give a little extra clearance and a film of WD40. Job done.

Now back to the Honda BlackBirds fuel injection strip down 😁

[Herbie]

On 11/10/2022 at 1:41 PM, Moleman said:

Just be careful about the size of battery, my CT uses a CR1632.

That shouldn't matter as it'll still be the same voltage, just the size that's different.

The numbers are the sizes, so a 2032 is 20mm diameter and 3.2mm high, which makes the 1632 16mm diameter and 3.2mm high. If you only have a 1632 you can use some cardboard or paper to pack the space left by the smaller diameter.

[Las Palmas]

6 hours ago, Herbie said:

That shouldn't matter as it'll still be the same voltage, just the size that's different.

The numbers are the sizes, so a 2032 is 20mm diameter and 3.2mm high, which makes the 1632 16mm diameter and 3.2mm high. If you only have a 1632 you can use some cardboard or paper to pack the space left by the smaller diameter.

And while 2032 is easy to find the little ones to the CT remote are not that often used and when finding a shop having these, they often have been laying around a long time waiting to be sold.

[Moleman]

7 hours ago, Herbie said:

That shouldn't matter as it'll still be the same voltage, just the size that's different.

The numbers are the sizes, so a 2032 is 20mm diameter and 3.2mm high, which makes the 1632 16mm diameter and 3.2mm high. If you only have a 1632 you can use some cardboard or paper to pack the space left by the smaller diameter.

Quite right, but the space in the key fob will only take a 16mm diameter Battery, not enough room for the CR2032. So it matters!

[Poundy]

Cr2032 doesn't fit, it's too big, I keep a spare 1632 at home with the spare key fob. I also rotate the key fobs at every yearly service to ensure it doesn't lose memory from lack of use. 😉

[royoftherovers]

1 minute ago, Poundy said:

Cr2032 doesn't fit, it's too big, I keep a spare 1632 at home with the spare key fob. I also rotate the key fobs at every yearly service to ensure it doesn't lose memory from lack of use. 😉

Lexus Dealer will change key batteries at annual service f.o.c. if you ask him Norman.