Hi all,

Unlocked my Octavia 3 (2018) estate this morning, put the key in the ignition, and the electronics went crazy. Every fault you can think of came up in quick succession. I took a video of it, but the file is too large to upload here. So, I've put it on my website and placed a link to it here and hope that's OK.

Any ideas anyone?

All I can add is that I've been having 'key battery replacement' warnings lately even though I've tried brand new Varta batteries in the fob.

That is going to be a VERY dead battery causing all kinds of errors on the CANBUS network. Do a CCA test on the battery. Replace if its 20% below capacity.

Thanks very much.

The battery was replaced on January 14th by a local garage!

My insurance company have arranged for a breakdown truck which is on its way to me as I write this. The car will then be transported to the garage for a battery replacement under warranty.

Possibly something as simple as a battery connector not correctly tightened when the battery was replaced in January.

Given you had a new battery fitted in January that would be the first area of suspicion, very unlikely to be the battery itself more likely fitting or incorrect coding but even with that I'd expect longer out of the battery but that would depend on your driving and use of electrics in/on the car.

Other than computer, electronics or electrics the alternator is best checked for full function, that it was fully charging, or at least trying to, the new (and previous) battery.

If it's not, and even if it is, a full scan tool report is needed with an appropriate VW scan tool that has a program for your model and year (or VIN) and that the vehicle program is fully updated on the scan tool before it's connected to your car and the scan tool and car batteries are in a reasonable state of charge. Without as mention you can get spurious scan tool readings and results.

Testing a battery and alternator can be with scan tool, dedicated battery tester or old school meter as the battery is so new and problems so pronounced the results should show obvious results of how to proceed.

See if you still need to be concerned about the fob after the car issue(s) is/are sorted, there can be a few easy fixes to those issues sometimes.

Loose battery terminal.

Flat battery

Many thanks for your replies.

The breakdown transporter guy came from 20 kms away within the hour guaranteed by my insurance company (Direct Assurance). He was able to start the car with a hefty jump starter unit. I then drove it 5 kms to the garage that fitted the battery in January. They parked it up inside the garage, switched off the ignition, then tried to restart it, and... no go.

So, the car is at the garage over the weekend and will be fixed on Monday.

I'm so glad I had that zero kms breakdown option on my insurance policy!

Glad you've got it sorted.

Certainly a battery issue - when mine went last year, the car absolutely sha* itself and lit up everything it could. If you have an OBD reader, you'll be able to see the faults are due to insufficent voltage.

I collected the car yesterday. The battery was faulty and has been replaced FOC.

1 hour ago, Gasconman said:

The battery was faulty and has been replaced FOC.

Possible but very unusual, more possible if the battery was old stock and not stored correctly, much more often the battery is blamed for other faults and mistakes - but it is possible to have a battery itself be bad but as far as I know quite unusual now from manufacture.

See if that also sorts your fob issue.

Thanks for reporting back, good luck.

3 hours ago, Gasconman said:

I collected the car yesterday. The battery was faulty and has been replaced FOC.

Remember that you might have some fault codes that will take time to clear (if you even scan it) and just check that the one touch window thingy still works!

Thanks for the tip; I'll check that 👍

Good point from OccyVRS..

Have a look in your 'Owner's Manual' for the car as to what might need resetting, if the power windows and roof were fully closed before battery disconnection then often it's just the time of day clock that needs resetting (I've no idea about seat memories). The windows reset will be in the 'Owner's Manual' if required.