KEYFOB BATTERY REPLACEMENT MG5 FL

[SUPERAL]

Following the low battery warning on my keyfob,I replaced the battery. However the key now refuses to function.
1. I have tried 3 x different batteries
2. The car does not recognise the key in the back up position.
3. The spare key still works fine.
4. I have tried the simultaneous lock/unlock process.

-Why does a seemingly simple process of changing a battery cause such a problem (I had similar issue with an MGEV 2years ago). What is my next step - go to a dealer?.

 

[Alb]

Perhaps the next step is to remove the battery and insert it the right way round!

 

[google1901]

There's a link for solution provided via another with similar experience:

View attachment 42850

 

[PeterHR2]

Did you do Step 9: 'Set the vehicle power mode to READY to resynchronize the key with the vehicle'?

 

[EvTek23]

There is a similar thread from @viki2410 titled:
Battery Key Change - Now won't work

The solution there was to disconnect the 12v battery

 

[SUPERAL]

Going it working. There was a disc on the negative side of the battery, which I peeled off and voila it worked. It was just too obvious to see! Thank you to respondents.

 

[Alb]

Was this the "nasty taste" disc?

 

[SUPERAL]

Was this the "nasty taste" disc?

Well, on the packet it does say "baby secure" so I guess it was. The packaging itself was almost adult proof.

 

[Alb]

Saved the baby and fooled the adult then
The last set of batteries I bought had the same but there were clear instructions on the pack about removal. It's a simple but very worthwhile safety feature.

 

[Lovemyev]

I always bought my fob batteries on-line from the usual places, like Amazon & E.bay etc.
Either Duracell or Everready.
All had good expiry dates, well into the future.
But then I started to noticed that the batteries were not lasting very long at all.
So, I decided to try a pack from our local supermarket, more expensive of course.
When I opened the Duracell pack and compared them to the ones bought on-line, the child warning sticker was not fitted to the on-line cells, but it was present on the supermarket cells?.
The supermarket cells lasted three times longer than the on-line bought cells.
I tend to think there are a lot of “fake” batteries being sold these days on-line.
I have therefore stopped buying on-line anymore.
Our VW Golf PHEV use to consume fob batteries faster than any other car I have ever owned, you could get 9 - 10 months top’s from a brand new good quality cell.
Apparently, when the fob is in the car, it “pings” a signal to the car every 20 seconds or so.
You can see this in action, when driving along.
There is a very small red led light in the fob.
Every 20 seconds it will flash briefly.
I guess this is why it was draining the battery very quickly.