Weird day today with my 2007 LHD 1.6MPI Octy II.

First, the passenger (front right!) window doesn't shut properly, tried experimenting with it a bit and each time it would stop and return to the open position at a random point. It appeared that at every third attempt it would switch to some kind of manual mode and let me roll it all the way up by holding the switch.

So we head off and after a few minutes we're on the M1, so as I'm going on the slip road and preparing to merge I hit the 'Econ' button to switch it off and get some cool air and pull the switches to roll up the windows. The passenger one predictably gets stuck so after I merged I pull it a second time and keep pulling it until I notice that I'm no longer accelerating.

I take a look at the dash and everything is lit up (I'm certain about the alternator, oil pressure, abs, engine, and while I was looking at it electric steering wheel went on as well!) so I turn on the hazard lights and safely pull out to the hard shoulder.

I try to start the engine twice without success, it looked as if the battery was flat as I could hear a short whir but obviously not long enough to get the engine started. This didn't make any sense but we got out of the car and I lifted the bonnet and went looking through my wallet for a number to call. A minute or two later, having found who to call, I decided to give it another go and this time it just worked! So we got back in and drove back home.

Only thing I noticed was that the aircon didn't work so air coming out of the dual zone climatronic was warm. It was OK yesterday so I doubt overnight it developed a need for a regas.

I plug in my cheap obd II/canbus reader and it reads the following errors:

engine: 19058 & 04772

abs: 00668

All of these are power related as far as I could tell, so no surprise there. I also checked all fuses and all were fine.

After reading some posts in the forum I used the climatronic to read the a/c compressor RPM and it is as it should be slightly higher than the engine RPM so at least it rotates. I can see engine rpm at tick over increase when I turn off econ, so compressor is adding load doing something when it's supposed to...

After 30 mins I gave up and we eventually did the trip we were planning without aircon and had no issues.

By looking around the forum I can see that aircon issues are not rare, but I wonder if what happened on the M1 was related to that. I also can't help feeling that it can't be a coincidence that the engine cut off while I was forcing the window up.

Any ideas would be appreciated, as it is right now I'll have to wait for Monday to have someone look at it.

When you switch the a/c to auto, are the radiator fans running?

When you switch the a/c to auto, are the radiator fans running?

There's only one fan on the radiator (unless there's a second one hidden somewhere!) and it's working. Didn't confirm if switching a/c to auto forces it on, since it was already running when I checked. Might be worth testing this now that the engine is cold I guess.

On my previous '02 Octavia the smaller fan failed which caused the A/C to not work so this was the first thing I checked.

Update: Just checked - switched on engine and as it was cold the radiator fan didn't kick in. Switched air con on and at both lo and auto settings the radiator fan didn't start. I waited for about a minute before giving up.

Everything else seems to be working, there's air blowing in and I can hear the flaps doing their thing.

Is it supposed to turn on immediately then?

Edited 27 May, 201214 yr by kkonstan

Do you have a voltmeter?. Check the battery voltage and the charging voltage. If you don't have one, most tyre dealers will have one and will do a battery and charging system check.

Sounds like low voltage to some controllers which is shutting down non essential systems (such as the aircon).

Do you have a voltmeter?. Check the battery voltage and the charging voltage.

Thanks everyone for their ideas so far.

I have a cheap multimeter and measured 13.65 with the engine idling and 12.05V with the engine off (less than 10 mins after an hour long drive, if I might add).

Looks like I could use a new battery even if this isn't the source of the aircon problem. It is 5 years old after all. Is replacing it as simple as buying an equivalent one and swapping the old one out or should I leave it to the pros?

So would the car leave non essential systems off even while the alternator is on though?

Edited 27 May, 201214 yr by kkonstan

12.05v is about 25% charged. Fully charged should be around 12.6-12.7v. With the alternator running I would expect 13.5-14.5v which yours is. In this case I would suspect a knackered battery giving low voltage to the CAN controllers.

A new battery should do the trick. To fit, undo the neg first and connect the neg last. You will probably get some warning lights but this is normal and they will go out after a quick drive.

If in doubt, get someone else to fit it for you. Most places will do it for free.

Before you go get a new battery, check both ends of the earth strap (the large cable that goes from the battery negative terminal to the chassis).

Before you go get a new battery, check both ends of the earth strap (the large cable that goes from the battery negative terminal to the chassis).

After leaving it to rest overnight, I measured again at both sides of the earth strap and it was at 12.40V

After leaving it to rest overnight, I measured again at both sides of the earth strap and it was at 12.40V

Sorry, I didn't make it clear what you were checking for. It is common for the crimps to go bad at the ends of the earth straps. You need to check that the ends are not corroded, have broken wire strands and are firmly attached to the chassis/battery clamp.

Car was due for an MOT today so I had the battery changed before at the MOT station (it wasn't in great shape) but no change with the AC I'm afraid.

I suppose I'll have to wait for next week and book it unless someone has another idea to try in the meantime.