I've had a few random alarm activations with my 19 plate Octavia over the last couple of weeks. The first time it went off, I walked away from my car, locked it, as you do, 2 mins later I unlocked it then sat in the drivers seat, closed my door, sat for around 1 mins, then put my key into the ignition barrel, whilst I turned it, the alarm went off for a couple of seconds along with the hazard lights, then then car started & all OK again. A week later, I parked my car up with the two front windows open. Got out of my car with my ignition key, walked around my car, got back in it again, shut my door, alarm went off again, used my fob to press the unlock button, alarm still was going off. I then put my keys within the ignition & turned it & the alarm then went off.

So I decided to play around a bit more with my alarm. After turning my ignition off, I opened the drivers side door & shut it again whilst sat in the car. 10 seconds later the car locked it's self without me touching the key fob. 

This is a few weeks after my head unit was randomly turning it's self off & on, so no idea if it's just coincidence or not. 

 

I then decided to check my car battery prior to starting my car, just in case my battery was low, it read 12.49v, after being stood overnight, so that looked OK. Although I've not had it load tested as yet. 

It does sounds like you have a module / modules that aren't going to sleep here....and this is obviously upsetting the car and activating the alarm.

 

Soooo.....I think you need to do two things:

 

1) Open up the bonnet, latch it, get an amp-clamp multimeter and let the car go to sleep (give it 10-15 mins), then check the current being pulled.  If its more than 16-25mA, you've got a problem.  Its then a case of trying to find out what is faulty.  Try using one of these: https://uk.rs-online.com/web/p/multifunction-testers/2003704

to check the current across each fuse.  Find the module that isn't going to sleep.

2) Blow out any dust in the ultrasonic sensors above the driver's head (where the sunglasses / sunroof switches are) - not a common problem in MK3, more a MK2 issue, but worth doing.

 

re: Head unit switching itself on/off.  Sounds like a its potentially got an issue.  If its one of the touch button screens, make sure that any residual finger grease is not causing issues

4 hours ago, varaderoguy said:

It does sounds like you have a module / modules that aren't going to sleep here....and this is obviously upsetting the car and activating the alarm.

 

Soooo.....I think you need to do two things:

 

1) Open up the bonnet, latch it, get an amp-clamp multimeter and let the car go to sleep (give it 10-15 mins), then check the current being pulled.  If its more than 16-25mA, you've got a problem.  Its then a case of trying to find out what is faulty.  Try using one of these: https://uk.rs-online.com/web/p/multifunction-testers/2003704

to check the current across each fuse.  Find the module that isn't going to sleep.

2) Blow out any dust in the ultrasonic sensors above the driver's head (where the sunglasses / sunroof switches are) - not a common problem in MK3, more a MK2 issue, but worth doing.

 

re: Head unit switching itself on/off.  Sounds like a its potentially got an issue.  If its one of the touch button screens, make sure that any residual finger grease is not causing issues

Thanks for the info. 

I've just had my battery load tested and it's good.

I also have the skoda extended warranty, software updates are not covered, probably amongst other stuff. 

At the moment it seems as though the car is suffering from random tech glitches or has done so for around the last month. 

I'll see how it goes, if I keep having issues with it I might take it into skoda or else where for a diagnostic, as I'd have thought there would be some fault codes stored with the the alarm randomly sounding or possibly a good auto electrician. 

The head unit has been A1 over the last two weeks, prior to that I had around two weeks of it randomly turinging off and then back on whilst I was driving without me touching it. 

This is my second mk3 Octavia, both have gave me reliability issues during the short time I've  owned them. I wont be buying a mk4 for certain, especially with their well known info screen software glitches. 

My Octavia estate is a very practical car, but plagued with electrical gremlins. 

If I ever find out what has caused the glitches ill post why. 

 

Edited 23 July, 20241 yr by Phoenixboy

Most gremlins like that are mostly Earthing Point issues or battery problems.  If the battery CCA is okay (anything less than 20% less than battery capacity is an issue), I would also check the alternator output too.  Software updates for Mk3/MK4 are done when the car is in for service.  Ask to make sure that all the software updates are done (and make sure they are applied across all modules too - partial updates break things).

2 hours ago, varaderoguy said:

Most gremlins like that are mostly Earthing Point issues or battery problems.  If the battery CCA is okay (anything less than 20% less than battery capacity is an issue), I would also check the alternator output too.  Software updates for Mk3/MK4 are done when the car is in for service.  Ask to make sure that all the software updates are done (and make sure they are applied across all modules too - partial updates break things).

Good point about an earthing possible fault. I bought my car from a skoda dealer 6 months ago, at that point software updates were up to date. 

The battery seems to be charging and holding its charge OK. 

Hopefully some codes would have been logged due to the intermittent alarm activations, also possible that the head unit screen was a separate issue. I had no issues with the alarm, locks or screen until around a month ago. It's also very intermittent. Screen has been OK now for over 2 weeks. 

I'll live with it until it annoys me enough to book it in for an diagnostic. 

Thanks for the info.