Changing Key Battery?

[Westyfield2]

I've got the normal "Keyless Start" (not the optional "Keyless Entry") on my A6.

One of my keys will always cause the car to say "Key Not Detected" and needs to be held up against the centre panel. Even then, it sometimes has to be held there a couple of times before the car will actually start.
The other key works perfectly - car starts first time every time.

So... has anyone else had this before? Is it likely to be a fault with the key? Or just a flat battery in it that needs replacing?

And if it's the battery in the key... any ideas how to replace it?

[Chesterfield313]

Not 100% sure, but think you should get a warning from the dash when the battery is low, most cars do.

I've not done it, but been told by a car dealer friend that you can buy batteries from Tesco for £2 and change them easily yourself, rather than the £25ish a dealer wants to charge.

[wja96]

The instructions should be in the manual.

[Chesterfield313]

The instructions should be in the manual.

Helpful, that response could end 50% of the threads on here.

Men don't read manuals, the majority of members on here are men. What should happen is through about a dozen posts people give how they think you can do it, a lot will be wrong, some (like mine) will be be vague, but heading in the right direction. Then eventually someone extracts the right information from a few of those posts. Or, someone reads the manual?!?!

[Aero97]

Changing the battery is easy - it takes a couple of minutes. As mentioned above, details are in the handbook.

My car did tell me on the DIS when both of my key batteries were low though. If yours isn't doing that you may have a different issue.

[Westyfield2]

Not 100% sure, but think you should get a warning from the dash when the battery is low, most cars do.

My car did tell me on the DIS when both of my key batteries were low though. If yours isn't doing that you may have a different issue.

Car hasn't told me anything about the battery being low - that's just me guessing . All the car says is "Key not detected" and to hold it against the panel.

For a while I just kept the bad key in a different drawer and only used the good key... but it's starting to annoy me now .

[ukgroucho]

Changing the battery is easy.

On the opposite side to the four rings logo on the metal part of the key is a little square button - push it in and pull, that pulls the 'regular' key out of the electronic key body.
Now turn the electronic key body over and there is another plastic button / catch that you press with your thumb and PULL - that will pull the battery caddy out of the key body.

Its a CR2032 button battery - do yourself a favour and buy a decent quality one or you'll be changing again in 12 months.

[Boxbrownie]

Mine didn't tell me I needed a new battery either, it just became obvious when I needed to hold the key so close to the door it looked ridiculous..........anhoo changed the battery (dead easy) and now I can once more lock and unlock from shopping car park distance!

[Westyfield2]

Thanks for the info . The lock and unlock buttons on the dodgy key still work fine, just won't start the engine properly!

[Boxbrownie]

Thanks for the info . The lock and unlock buttons on the dodgy key still work fine, just won't start the engine properly!

In that case it seems odd that although the key is so weak it cannot start the car but it is strong enough to open the car from a distance, I wonder if there is more to it than a weak battery?

Still worth changing the battery though, they are only a couple of quid for a good one, and it may solve the problem even if it seems an odd one.