Breezy_Pete

Couldn't resist getting some better info before dark and before the engine cooled right down again. Log attached. Max cat temp around 650C, which isn't far from red hot according to google. That was with revs held up at about 2k, cat temp drops back by about 50-75° to 585-ish when engine is left to idle. Coolant temperature showed 90 on gauge when the VCDS temp was only 60 which is a bigger fudge-factor than expected. Never got higher than 84 in VCDS, even after a further 11 mins of running, which makes me wonder if a new sensor is due. Cat temp log Jan 2021.CSV

So, I warmed up the engine (1.2 12-valve 2005, code AZQ) whilst stationary, from an ambient of 0°C over about 12 or 13 minutes. Held revs higher (around 2000) for some periods when I got a bit impatient after 7 or 8 mins. Coolant temp showed 90 after about ten minutes. Highest temperature seen on IR thermometer was 270°C, pointing at manifold next to oxygen sensor and at cat body just below heatshield, same in both locations. Reached that temperature within about 3 mins of start up. Unfortunately, when I look at the IR thermometer, it has a upper range maximum of 270! So that wasn't the best tool for the job. No sign of glowing red anywhere under the heatshield though. I'll try reading some temps with VCDS next time I start it up, I think there are some measuring blocks that can estimate the manicat temp via the resistance of the oxygen sensor heater.

I'll go out and observe ours shortly, maybe even point an IR thermometer at it while it runs for 10 or 15 mins.

That corrosion looks like the cause of the problem, in my opinion. Do what you can to clean up the female contacts and then exclude water from the area however you can.

Maybe soon but... Your battery charging didn't result in a very full battery, as judged by the 12.4ish volts. It should be more like 12.6/12.7 when fully charged. I would've persisted more with the charging and put the charger back on it the next day to see if that brought it up more.

The single wire on your alternator is a LIN data connection, so I wouldn't expect its voltage to be a useful measurement. The charging voltage being a fixed 14.2 suggests that the alternator has defaulted to 'traditional' behaviour which may be consistent with a disconnection of this LIN data stream at either alternator or battery management module (near batt negative post). Such a disconnection will result in start/stop being inhibited. The overnight voltage suggests that the battery is pretty healthy though.

Yep

I'll just check if there's another fuse for the relay coil. Yep, fuse 8, 15 Amp one apparently. I think that one may cover a bunch of other stuff too though, so I think it would've affected other things if blown.

Chain.

Oil temp sensor is (usually) combined with oil level sensor in the sump. The temperature may just be lagging behind water temp more than usual due to cold ambient, and if you run for a bit longer it'll start showing? Minimum is 50°C to be shown, I believe. May not be enabled/displayed if the car is on fixed annual servicing though?

Do you have a multimeter? You say the fuse looks fine, but measuring battery voltage on both sides of it would be more convincing.

Get some pics as you go along tomorrow, may help others in future.

I think it may be like this: Skoda Workshop Manuals > Octavia Mk2 > Vehicle electrics > Electrical System > Wiring > Fuse holder and relay carrier > Removing and installing the E-box (relay and fuse carrier in the engine compartment) > Vehicles up to MY 05 (workshop-manuals.com) (first image).

Maybe just try removing the battery retaining screw, then see if you can move it towards the engine enough to get access under the ebox. I seem to remember the relay carrier may slide outwards, towards battery, but that may have been a different design.

0AQ, 0AR, or 0AS. See part numbers etc here (view on a non-phone screen to be sure of seeing all the info columns.) suspension; shock absorber (spring cyl.) - Fabia(FAB) [EUROPA 2012 year] (7zap.com) I seem to remember that the actual bar diameter is a couple of mm bigger than the numbers shown corresponding to the three PR codes 0Ax. There's some squish of the rubber when fitting. View on a non-phone screen to be sure of seeing all the info columns.

See if there's a PR code on the build sticker that tells you the size. I'll post a link to a suitable etka page for the options in a minute.

Dunno, and don't know quite where to find out; but I'd guess it would be closer to 4 litres than 5. Let us know. Edit, found one site which reckons same engine in a Golf takes 4.3l. https://www.car.info/en-se/volkswagen/golf/golf-variant-15-tsi-act-m6-2018-16418778/specs

The battery is an electrically dumb device. All the talk about 'coding the battery' is misleading; you actually code/educate the car about the size/type of battery being installed. The battery has nothing within it that could contain any code.

Check fuse 24.

Suggestion: NEW GENUINE SEAT IBIZA CORDOBA 6L SKODA FABIA 1.9TDI ASZ OUTER CV GAITER BOOT | eBay May be out of date with respect to the use by date, possibly, packaging not shown. I'd buy it and use it at that price even if it was a few years out.

I'd just fit a new boot. The rusty surface of the CV is pretty irrelevant.

Assuming your car had a diesel engine, that'll be a fuel cooler. Should be fine to drive as long as it hasn't ruptured any of the fuel pipes, which I think you'd notice.

I've watched and enjoyed the first three already. Third one just now has finally motivated me to strip down the box that's been sitting outside my shed for a couple of years. Like the fella's attitude and delivery, is it you @AJR77?

It might be an option listed on the build data sticker on the boot floor. Can you post a photo of that sticker? The code may well start QN followed by a number. Handbooks tend to describe every option that might be fitted, usually with a * for non-standard items.

The engines I've looked at and linked you to on ETKA are CTHD and CTHE. Are you viewing this on a phone? Sometimes that results in some missing columns of information, important ones like the part codes!