Breezy_Pete

I think the J519/ module 09 unit is called Onboard supply control Unit sometimes, which could be abbreviated to power supply unit or PSU The update may well have included software modification to specifically not allow that alarm horn confirmation of locking etc. I seem to remember reading about some EU ruling that made it illegal, for noise nuisance reasons. It would be a bit tragic for you if that was all that the update was for.

On that link I gave you before, about halfway down the page of diagrams there are two for rear brake hose set-ups depending on whether 4x4 or not. Pick the right page out of those two, find part number for relevant hose. Hint: if you can't see part numbers try viewing on a computer rather than phone, phones seem to sometimes not display all the columns in the tables.

There are three different rear disc set-ups for a 2008 mk2 Octavia, the last three diagrams on this page: https://skoda.7zap.com/en/cz/octavia/oct/2008-419/6/ If your car still has the build data sticker on the boot floor near the spare wheel well, you'll find one of the three PR codes starting 1K followed by a D, a P or an F. From what you've measured you'll most likely see 1KF, the 41mm piston variant with 260x12mm discs. ECP lookup by reg is just rubbish in my experience. Phoning them may give better results.

Same here.

Screenwash sensing might be coding of instrument cluster, thinking about it. Again easily recoded to remove if your reservoir lacks the sensor.

The coding in the 6Q1 control unit is probably different to how it was in your old one. Not sure if all of those things are in that unit though. VCDS could recode easily if necessary.

The 6-valve HTPs do seem to have a tendency to overheat and crack their exhaust valves. Compression test will discover if this has happened.

If the spark plug has failed completely the engine will only be working on two out three cylinders which will make it very lumpy indeed. Not sure about the rattling. Compression testing is where a pressure gauge is inserted into the threads where the spark plug normally goes. You take out all three plugs and test each cylinder in turn by spinning the engine over on the starter motor and seeing what maximum pressure is registered on the gauge for each cylinder. How quickly the pressure rises can also be useful info. All three cylinders should give similar numbers if all is well mechanically. Your mechanic will be familiar with the process, shouldn't take long or cost much

As a first step ask the mechanic if he checked the spark plug of cylinder 1, and to do so if he didn't. If that's OK, probably the next step is to get it compression tested. Is it the 60 bhp 6-valve engine or the 70 bhp 12-valve?

Local scrappie, or someone breaking a car on here or ebay? Searching by part number certainly throws up some horrendous prices on used units!

No, you can't see anything useful with just that end cover removed, I mis-remembered.

I think that would only work on a pre-facelift car, though I have no idea what the difference is. Get the door card off to see the part number on yours, I suspect it'll be 6Y2959802 SK1. Check all the connections for corrosion while you're there.

I'll pop out soon, after my dinner has digested a bit and see if I can get a photo of it on a mk1, and the end cover that may or may not be the same on a mk2.

As far as I know the ignition barrel and immobiliser pick-up coil are 'dumb' things that just fit the key and pass immo signals from the fob to the cluster, but the immo signal needs to be the one the cluster is expecting, so from the same car as the cluster. Are we talking about radio remote central locking or key-in-door central locking? Not really understanding why your 'matching set' central locking unit didn't work but your old one did. Was the part number exactly the same, including letter at the end?

So neither window works off the switches in the driver's door, does the passenger side one work from its switch? If not it has to be either a broken wire in the door hinge area or a failure of the driver's side window module, I think. You didn't answer about the dampness status of the cabin? When you've investigated wiring in the door hinge area have you managed to get the rubber boot to sit nicely against the a-pillar metalwork afterwards? Easy to create a leak there straight onto unsealed connectors.

Now that you have power at the main 25A fuses, do the windows open if you turn the key in the drivers door to unlock and keep it held round. And go up again if you lock and hold key in that rotation?

Yep, you have all the right info and understanding. The 25Nm isn't easily done with a torque wrench since you have to counterhold the (flattened) top of the shock rod and use an angled ring spanner on the nut, but I don't think 'guessing' that one will be a problem. It's usually a nyloc or other type of self-gripping nut. Bottom nut and bolt are supposed to be replaced with new ones, as are the top bolts but I think if they aren't too corroded you'll be OK re-using.

Check fuse 11 (5 Amp). Is the car still damp/leaking or did you fix that?

Still a bit low on the engine running figure, but not enough to explain any misbehaviour I don't think. I'll have a look at the relevant wiring diagram for the window-related stuff in a short while. Pretty sure there's another fuse involved that you haven't mentioned.

Check the brake servo vacuum hose, particularly any junctions of hard plastic sections.

Item 15 here. Diagram shows LHD so mirror everything for RHD cars. https://skoda.7zap.com/en/cz/fabia/fab/2014-697/8/820-820020/

Recirc motor is at the extreme end of the dashboard, heater flap one is different/separate. There may be a cover that can removed to see it. Not sure on a mk2, or mk1 Fabia, but on 9N Polo there's a clip off cover right on the end of the dashboard that you can only see with passenger front door open. Think lower dash trim and glovebox probably also both need to come out to get sufficient access as it's a fiddly operation. Getting gears to mesh correctly while clipping the thing in place is not easy, but I managed it with biggish clumsy hands so probably not too bad.

What year is the car Phil?

13.85 is rather low, maybe double-check that. Is it definitely a mk1 Fabia with 6Y in the 7th/8th characters of the VIN? 2007 would sometimes be a mk2.