Hi all.

I have a 2019 S3 that is giving me an ignition light funky disco  from time to time. The ignituon lights stay on or flicker even with the engine running.

Sometimes the dash goes blank and gives me "Ignition powered off" or similar and, according to my better half to whom it has just happened, the heater fan goes off.

It will start and drive as normal and has occurred while driving.

I don't know if its related but each time I start the car the rear occupancy/outside temp display, which are at the same location on the dash, flicker between the two displays.

I have had the car since September and its happened 3 times including today.

Any suggestions welcome.

Thanks

Andy

The prime candidate to my mind is a dying battery. The recent cold weather is revealing the weaknesses of all batteries. If it is the original five year old battery I would not hesitate to change it; if it is more recent I suggest you get it professionally tested before buying a new one. Make sure you get any new battery coded to the car.

Ok thanks. It's not something I would have considered as it starts on the button.

I have a decent tester so I'll give it a try.

Edited January 9, 20251 yr by Andy_B

The ability of a battery to crank the engine is not proof that it is in good condition.

I concur Clifford,

Having recently purchased a new battery I did have some teething problems which I later found out was to do with the battery not being fully charged. With hindsight I should not have assumed a new battery would be fully charged, quite the opposite in fact and perhaps good practise is to fully charge a new battery no matter what!

I do recommend the CTEK MXS 10. Although pricey, I feel its about the best for any battery that you would ever own.

Terry

Ok, here's battery test results

Battery is date coded 06/23. Temperature was zero degrees. The car had covered a 25 mile journey at 10.30pm the previous evening and the test was at about 10am.

2nd pic is test before starting

3rd is test with engine running (I think 🤔)

4th and fifth self explanatory.

No idea if this tells anyone anything but happy to consider any suggestions.

Car will be left until Thursday evening and I will repeat the test.

Andy

What were the results of the retest Andy? Please transcribe to text as reflections in your photos make them difficult to read.

Battery test from this evening after being left for four days. 16% charge looks rubbish but it started on the button.

I thought I'd posted the updated test. Hadn't pressed send!!😁

Edited January 19, 20251 yr by Andy_B
Typo

16% looks rubbish because it is rubbish, and needs to be replaced. As I said on Jabuary 10th

"The ability of a battery to crank the engine is not proof that it is in good condition."

I'm a old school "if the battery is knackered the car won't crank" type of guy, but every day is a learning day 😄 I am ordering one tomorrow.

Just got the VCDS diagnostic kit so will be attempting the coding too.

13 hours ago, Andy_B said:

I'm a old school "if the battery is knackered the car won't crank" type of guy,

I was too until the car suffered simultaneous  unexplained electrical problems that all magically disappeared on fitting and coding a new battery. It was a hard lesson to learn.

I know of two other threads on the forum in which the owners refuse to accept their batteries are defective because a meter reading says it still has 12 volts. As the old adage goes "you can lead a horse to water but you can't make it drink."

I didn't refuse to accept it.

So, my horse has drunk the water and I've fitted a new battery .

All good so far but saying that I haven't had disco ignition lights for the week prior. 

I'll update in a month or so, hopefully it's been put to bed.

Andy

What make of battery did you buy Andy? 

I replaced like for like Bosch S5 A08. I just changed serial number in VCDS to include the date I swapped it.

Glad to hear it's sorted. Giddy up Neddy.

Still good so far.

Good news Andy, and thanks for letting us know.