Help ! Electronics gone haywire.

[Will777888]

Yesterday afternoon we had some very heavy downpours followed by a damp night without rain but with a lot of condensation around.

At 00.30 this morning, I was woken by my car alarm. The alarm has always been a bit temperamental; normally just unlocking and locking remotely with the key fob shuts it up. This time, that would not work. I went out to the car and noticed that not only were the hazards flashing and alarm sounding, but the dashboard was lit up like a christmas tree, warning lights flashing on and off at random. The stereo and heater had come on. I was able to silence the alarm temporarily by playing with the central locking, I removed the negative wire at the battery and went back inside. I then spent a restless night worrying about a bank balance busting failed ECU.

When I went to the car this morning at 08.30, I reconnected the -ve wire. The engine did start but a few warning lights remained on: steering wheel symbol (low power steering fluid ?), handbrake on, ABS fail and ESR off. Other electronics seemed OK (headlights, indicators).

I returned to the car at 09.00 to take my littlun to nursery and the car started OK again but with the same warning lights. I arrived at nursery (2 miles) and was surprised that the engine did not stop after I turned and removed the ignition key. It was as though the key had remained in the 1 position – stereo and heater still on. Stupidly, I stalled the engine (on purpose) and immediately found that it would not re-start. I was able to restart it by bump-starting it. Same again when I returned home.

I'm hoping this is water ingress that will dry out and cure itself. Otherwise – ECU ? £££ :-( Dashboard wiring got damp ? I have had a brief search on the forum and found nothing similar. No sign of water in the cabin.

Anybody had similar and got to the bottom of it ?

Car is a 2004 Octavia 1.9 tdi PD. It has otherwise been fairly reliable in my 19 months of owning it. 

Thanks,

Will.

[Will777888]

Quick update. I strongly suspect the cause was water ingress into or in the loom around the fuse box in the engine bay. I had the LH headlamp and airbox out and blew a 2,000 W hairdryer at the area for 3 hours or so. Also unplugged some of the loom connectors in attempt to dry those too. Also sprayed plenty of WD around the place. Seems much better now. No more warning lights with the key out / position 0. Turning the key back to 0 stops the engine, as it should. Remote central locking works correctly. Only one warning light remains on with the car running - the steering wheel one.

Whilst I was waiting for it all to dry, I gave the EGR a spring clean too. I also knocked up a rudimentary cover from a paint roller tray which fits over (and is larger than) the fuse box. This should hopefully stop any further water ingress into the area from the gap between the bonnet and the wing.

Time will tell if I cured this strange problem. Will post another update soon.

Edited 9 October, 2014 by Will777888

[Will777888]

Thanks Mike, that is reassuring. It's orange. Not been out in the car yet since drying out the wiring.

[Bishman]

I think I might have a similar problem to this.  My wife took the car to work last night and when she came home this morning, reported that the car keeps flashing at her (lol).  As soon as you lock the car and leave it for about 20 seconds the hazards start flashing, I believe this is the alarm going off as I was told the horn for it doesnt work anymore when I last had it serviced.  I drove it to work today and no lights on the dashboard but the alarm keeps triggering so its currently 'flashing' at people in the car park.  I was thinking I might take out the fuse for the alarm system?  (35 in the dashboard I think according to the owners manual)

[Guest]

@Bishman

Disable the interior motion sensing by pressing the button by the driver's seat B pillar, this will help diagnose what's triggering alarm.