PipH

Have a look at this diagram :- https://skoda.7zap.com/en/cz/octavia/oct/2010-663/1/121-121053/ Part No 88 is the gear oil cooler. ( Gearbox oil to coolant heat exchanger ) It connects via pipework to part No 15 ( bottom right ) which is the gear oil cooler thermostat. But i'm only guessing at your engine code, check that first.

I understand that some 1.9PD's had DPF's fitted from around 2008. Do you know if yours has one fitted. Engines usually sound a bit unstable & noisy when doing a regen of the DPF.

The coolant sensor could well be giving a false reading. If the ECU thinks the engine is still quite cool it will run in a different mode which will result in more particulates. Whether it is the cause of your problem I couldn't say, but certainly need addressing.

On your freeze frame data it shows " Coolant temperature: 60 °C " which is very low if the engine had been running for a while. Check with VCDS that the engine is getting up to temperature ( 90C ) within 4 or 5 miles of starting from cold.

It sounds like one of the battery connections is loose or corroded, or the earth cable where it attaches to the chassis. Also check the engine bay fuse box where cables are bolted on, that they are secure & no corrosion.

When the engine is trying to regen the DPF it injects extra fuel late in the exhaust cycle which doesn't get burnt in the cylinder, but goes into the DPF to heat it up & burn off the soot. You shouldn't be able to smell this in the car. I think that maybe you have a leak somewhere between the exhaust manifold & DPF which is affecting the regens as well as leaking into the engine bay/ cabin. Have a good look around this area for black soot.

The nut heads that should be on the other ends have the dimples in them. Looks like they all came loose & just fell apart. You may just need new screws & dimpled nuts then if they are available. ( & some Loctite )

A 30 min drive should easily regen the DPF, as long as you get to around 40MPH for a few miles. Don't get hung up on revs, as long as the engine is revving over 1800RPM it will be fine. Do you have a DSG ? No error when trying to do a regen, it's just doing what it should be doing.

It sounds like your engine is trying to regen the DPF. If you went for a drive 10 - 20 miles, the DPF should be able to regen & tickover would be back to normal. Suspect you do a lot of short journeys.

Undo the centre bolt & the 3 leg coupling will just pull off the splines. Once that is out of the way you will see a circlip that holds the pulley on. Remove the circlip, take the tension off the drive belt & the pulley will also just pull off. You will see there are 3 special bolts on the pulley with dimples in the heads that the 3 leg drive fit into. If the compressor is ok, they must have worn. You could loosen them & rotate 180 degrees to get another life out of them or buy replacements if available. You will also need the new 3 leg coupling.

There are several different makes of compressor fitted & all have different drives. Have a look at my old post where my compressor drive was rattling but still working. Replacement drives are now available on eBay https://www.ebay.co.uk/itm/A-C-CLUTCH-DISK-DELPHI-DH5-SKODA-OCTAVIA-SUPERB/392275299499?hash=item5b556e0cab:g:e2cAAOSwnO5cruv3 But it does sound like your compressor may be goosed, which caused the drive to fail as it is supposed to if the compressor seizes in some way.

Have a look at this link :- https://www.citizensadvice.org.uk/consumer/buying-or-repairing-a-car/problems-with-a-used-car/ If you send him a recorded letter, it needs to be a " letter before action ". ( there will be templates on the net for this ) But in doing so, you need to be prepared to take out a " small claims action " if he still does nothing to resolve the issue. This will cost you around £150 & await a court date. All that time your money is tied up in a faulty car, & when you win your case you then have to hope he has money to pay you. ( Can't get blood out of a stone, as the saying goes ) It's much better if you can work with the dealer to come to a deal you are both happy with.

I think on an auto, the ECU needs to know that the gearbox is in Park or Neutral before it will allow the starter to turn. So there will be a switch either on the gearbox or selector which may be faulty.

http://wiki.ross-tech.com/wiki/index.php/01130 They seem to say either fuse, wiring or ABS module. Might be worth getting the wiring diagram to check that. I would have thought you could get one from a breakers cheaply enough. Change it & code it, rather than sending it off for repair. Seem to be available from about £20 on eBay. You will need the old units coding via VCDS before you remove it.

Whether the exhaust gas gets recirculated once or a 100 times, there is only one way out for it, & that's through the DPF. The EGR doesn't act as a filter.

If the resistor pack keeps burning out, it could be that the motor bearings are a bit tight & need some lubrication.

No problem at all for the DPF. EGR reduces combustion temperature, so is inoperative when the DPF needs to regen.

It's quite probable that the ECU has more than 1 12v supply to it, but you need the wiring diagram ( which Wino may have access to ) to see. Also might be worth removing the battery lead for a couple of minutes, just in case something in the ECU has got in a tizzy & needs resetting.

I used one on my son's Tiguan when the EGR started to act up, but that is on a 2l engine, so slightly different. But it has worked 100% since fitted about a year ago.

You can fit one of these if you want to disable the EGR. https://www.ebay.co.uk/itm/09-EGR-AGR-Valve-Simulator-Emulator-Plates-for-VW-Audi-Skoda-Seat-1-6-TDI-CR/183869312895?hash=item2acf770f7f:g:A9gAAOSwqPFdHF~4 No remap or other changes needed.

The timing comes direct from the ECU to the injectors. If this is how it has been since the belt was last changed, I wouldn't touch it until it needs doing again.

The part listed on the paper is the engine ECU, which is one of the most reliable bits of the whole car, so is very unlikely to be faulty. https://www.ebay.co.uk/itm/COMPUTER-ECU-VW-GOLF-7-2-0-150-KM-04L906021DT-0281018498-WARRANTY/202661752022?hash=item2f2f94ecd6:g:VEwAAOSwO2pcwZL8 You need to take the car to someone who has VCDS diagnostics or the dealer system to get an accurate fault diagnosis.

The high pressure pump isn't " timed " to the engine as such. It just provides a flow of high pressure fuel to the rail. There may be an ideal position for the sprocket, to even out the load on the belt.

You have a 6 month warranty for a used car bought from a dealer. https://www.citizensadvice.org.uk/consumer/buying-or-repairing-a-car/problems-with-a-used-car/ It is nothing to do with the AA warranty he has supplied. Just speak to the supplying dealer clearly without loosing your rag & explain you want the car fixed at his expense.

Looks to be the same problem as in this post :- You will need a new metal type intake manifold that does away with the vacuum module & swirl flaps.