Key battery warning

[5teep]

Started getting warnings again today after changing the battery just 2 weeks ago. I think it must be a bad battery (was in it's packaging in a drawer for x years). So I stopped in by another supermarket and bought some branded ones.

 

[Alb]

I've seen the same on other cars.
Best to stick to premium brands.

 

[Smurdley]

Loading the car up yesterday with the key in my pocket. When I got in the car to drive off a warning flashed up on the screen; low key battery warning. I've never seen this before and it disappeared after a few seconds. I wouldn't think the battery is low as ths car was serviced about 3 months ago so guessing it was a digital hiccup. Quite a useful feature, must have a read through manual.

I had the same warning. My car is just over 2 years old with 8500 miles on the clock. I'm amazed it needs a new battery so soon. Is it easy to replace?

 

[SimonomiS]

I had the same warning. My car is just over 2 years old with 8500 miles on the clock. I'm amazed it needs a new battery so soon. Is it easy to replace?

Maybe you had a slightly defective battery. In any case, it's very easy to replace - the plastic case splits apart by prising open and you'll see the battery and housing. The case then snaps back together easily!

 

[Alb]

The procedure is in the owners manual:

 

[Amun]

Page 113 of the FL manual, as different key type

 

[jackois]

Changed mine out this morning as I coildn't get into the car with it.... sadly it turned out, after the AA mans visit, the the car's 12V battery was flat.

His diagnostic gear, afer he got the car powered up, didn't show any problem with the battery per se. He advised letting it sit switched on for 30 to 40 minutes and see wha it's like tomorrow... I still have a feeling that the 12V will need to be changed out.

 

[rolydog2001]

As an automotive locksmith I can assure you button cell batteries dont last forever in the pack, if I had a £ for every vehicle key fault I had attended where customer had just fitted a new battery I would have hundreds of £'s by now. Both quality and cheap ones are often dead out of the packet.

 

[Shrink Proof]

I got the low key battery warning around Christmas. Thought it was a function of Highland winter temperature as all was OK for a few weeks. Then it returned. It started appearing with increasing frequency so I changed the disc battery in the key; I inserted a brand new Duracell disc.

Outcome? The car doesn't recognise it. The key is now useless. The dealer reckoned it has to go to the garage to be reprogrammed from scratch. Luckily the spare key is OK to use while I wait for the appointment but the original key remains dead. If this happens with every battery change I might start asking for a replacement to be fitted at each annual service.

So only change the battery if you're sure the spare key is working OK.

 

[mj224]

I changed my battery in the keyfob last month. 3 years and 3 months.

Nothing is stored in the key, just a code to open the door and validate the car start etc...

 

[maskull]

Changed mine out this morning as I coildn't get into the car with it.... sadly it turned out, after the AA mans visit, the the car's 12V battery was flat.

His diagnostic gear, afer he got the car powered up, didn't show any problem with the battery per se. He advised letting it sit switched on for 30 to 40 minutes and see wha it's like tomorrow... I still have a feeling that the 12V will need to be changed out.

Changed mine a couple of months back . I first checked my spare key was working .As all was OK ,I changed the battery and it worked OK. It's a mystery why yours didn't . As mentioned above the codes should be stored in the key's NVM

 

[Shrink Proof]

I reopened the key and solved the mystery - a (very small) sticker on the bottom of the disc battery, something I've never encountered with previous disc batteries. This was the first one from a brand new pack. Following the instructions in the MG handbook, I dutifully inserted it +ve side up. The battery had emerged from the pack +ve side up, so I'd never turned it over (why would I need to?); as a result I didn't see that Duracell have started adding a pointless extra to their product that, until removed, makes it completely inoperative...

 

[PeterHR2]

Did the sticker have a graphic of a baby with the tongue stuck out? They (Duracell anyway) have started adding repulsive-tasting stickers to CR2032 batteries and a few other coin-type batteries to prevent ingestion by toddlers.

 

[Shrink Proof]

Did the sticker have a graphic of a baby with the tongue stuck out? They (Duracell anyway) have started adding repulsive-tasting stickers to CR2032 batteries and a few other coin-type batteries to prevent ingestion by toddlers.

Once I'd turned the battery over I did indeed find a picture of a baby with the slogan Repulsive Tasting. Which I considered irrelevant as I've never wanted to eat a baby anyway.

 

[CarlThom]

Loading the car up yesterday with the key in my pocket. When I got in the car to drive off a warning flashed up on the screen; low key battery warning. I've never seen this before and it disappeared after a few seconds. I wouldn't think the battery is low as ths car was serviced about 3 months ago so guessing it was a digital hiccup. Quite a useful feature, must have a read through manual.

Trouble is the battery and the fob may have been manufactured some time ago and be nearly flat. Our MG5 came with only one fob from new. Had to wait for delivery from China then take car in to have it matched up. Seems there is a large box of these things in stock somewhere waiting for issue