Locking issues - battery related?

[Little_Lee]

Jan 2018 Audi Q7.

For the past week I have been getting locking problems.  

When I leave the car and lock it the mirrors pull in / lights flash / alarm light foes red but all doors are still unlocked.

You hear a faint locking noise but not as loud as when the doors actually lock.

Also sometimes when I return to the vehicle and unlock it all 4 windows drop about 10 / 15mm.

I have changed the batteries in the remote but it's still the same.

I wondered if it was the battery so I put it on charge and as soon as I did the car locked by the key.  Coincidence?  Next day locks play up again.

I'm not having any starting problems to suggest low battery and no warning lights / errors showing on dash.

 

Any one had similar or thoughts whatbit might be?

[cliffcoggin]

That recharging the battery immediately allows the doors to lock strongly suggests that the battery is weak. If it is the original battery it undoubtedly needs to be renewed.

Note that the ability of a battery to crank the engine is not an indication of it being in good condition,

[Little_Lee]

On 1/21/2025 at 6:36 PM, cliffcoggin said:

That recharging the battery immediately allows the doors to lock strongly suggests that the battery is weak. If it is the original battery it undoubtedly needs to be renewed.

Note that the ability of a battery to crank the engine is not an indication of it being in good condition,

Did realise that... assumed it would have trouble starting.

Does a new battery really need coding or can I just swop the battery myself 

[Little_Lee]

2 days after charging and the locks working again... now playing up once more.

My interior leds changed back to the standard blue and lost my preset radio channels etc

[Little_Lee]

Is there an easy way for me to tell if it is the battery or if its something like the alternator not charging it

[cliffcoggin]

Lee.

There is no easy way to test the battery yourself. A simple voltage test will tell you nothing abouts it condition. You can get the battery tested professionally if you want confirmation, but as I mentioned earlier an eight year old battery is overdue for renewal, and it will have to be coded using VCDS or OBD11 or similar.

[cliffcoggin]

PS. Loss of radio presets and other odd electronic faults are classic signs of a clapped out battery. Other possible symptoms you may notice are: limp mode, air con failure, erratic gear change on an automatic.