sepulchrave

The RFID chip in the key is read by the instrument cluster using an inductive loop antenna around the ignition lock, these can give trouble due to dry joints in the instrument cluster where it plugs in.

The first place I would start with a 6V is with a compression test, you can do this even though it won't run.

If you've fitted the wrong ECU then I'm not surprised it won't start! Like @Breezy_Pete says, it's almost NEVER the ECU at fault so refitting the old one should get it running again.

Unlikely, alternators do get hot, that's why they've got all those slots in the casing to cool them down. It's possible that the charge controller itself is faulty resulting in the battery light blinking on and off.

The fault code suggests the sensor itself is faulty rather than the heating element, given the incredibly low mileage I strongly suspect it's badly sooted up, cleaning it probably won't work but may be worth a try.

I think you're right, test the wiring to the switch first, then the reverse switch itself.

Yes, that's fine

Try dropping a little oil down the plug hole before retesting the compression to rule out any bore glazing.

No, the compression figures are certainly not acceptable, cylinders 2 & 3 are nearly 15% down on cylinder 1, this alone is reason enough to account for the problems.

No damage but you can easily test them with a multimeter without removing them.

It's usually indicative of a tired pre-cat lambda probe leading to either a slightly rich or slightly lean fuel trim depending which way the probe has gone, this error is being flagged up by the post-cat lambda probe as either too much or too little oxygen in the exhaust gases. You can cure it temporarily by simply clearing the code which sets the fuel trim back to default mapping.

Ah, ok, I think the SDI fuel temperature sensor is mounted on the mechanical fuel pump.

You don't need to grease them because rubber is self-lubricating, you should try listening occasionally!

No it doesn't. Those pins in the rubber bushings purely keep the caliper from falling off, all the load is taken by the carrier assembly into which the pads are inserted, those pins carry no load whatsoever and do not wear out, that's why they're rubber so that they can accommodate any slight misalignment when the caliper clamps down on the pads.

Why do you need those, they don't do anything?

Yes the front end has to come off, it's a lot of labour.

The SAE viscosity index is prehistoric, from way back before synthetics, synthetics have made it all about the additive pack, viscosity is largely redundant, modern oils flow like water when hot but are as slippery as ice.

The only Fabia manuals that really give trouble are the six speeder in the VRS Mark 1, usually in tuned cars because there's so much torque and the five speeder in the SDI which also struggles with the low RPM torque.

The fuel temperature sensor is usually located in the top of the fuel filter housing. It does sound like a neanderthal mechanic has damaged the wiring loom while removing or replacing the gearbox.

No, YOU get a grip, this sequence of posts I've been involved with has been about @jonnieboi82 and the erroneous 0W20 fiasco upon which you kicked off like a hysterical Muppet (your words, not mine!). I'm not trying to rewrite history because I'm not interested, you behave like a spoilt child when you don't get your own way. @jonnieboi82did NOT get the wrong oil fitted at his service, your demagoguery and scaremongering made him doubt his own sanity, what you've done is make anyone with a Mark 2 VRS completely paranoid that if they don't follow your ritual nonsense, according you the importance you feel you deserve then their car will go pop because they didn't listen to you. So here it is again for you, @briscaF1got it right so I backed him up. Oil brand is not important, nor viscosity because it's an archaic AMERICAN standard, it doesn't MEAN anything in modern high performance engines, what matters is the engine manufacturers specification, this relates mainly to the additive pack rather than the synthetic base stock itself. If your technical education did not include a module on tribology then that's fine but just stop shouting everyone else down and frightening owners with baseless scaremongering.

Resistance is largely irrelevant to HT systems, the resistance is only there to reduce RF interference. The resistance across the plug gap is infinite, however the HT voltage can jump across it easily.

Don't be sorry, you're absolutely right to call this nonsense out if it doesn't pass the sniff test. It's called putting the cart in front of the horse, it's like a doctor giving someone with a brain tumour some paracetamol for their headache. Ridiculous.

Like I said, anecdotal...

Seriously? This isn't about attitude, opinions or your limited experience as an owner/driver. It's a technical matter based upon the existence of facts, I've seen every kind of engine failure you can imagine, believe me there really aren't that many reasons why an engine goes pop and the reason for this is that engines all work the same way, are made of the same stuff and get driven by the same idiots.

You lot talk such a load of crap about spark plug brands, oil brands etc. You are complete brand fairies, as if the one thing that can save a posters car is the anecdotal nonsense trotted out by you and others like you so everyone hangs on your every word. I at least have a technical education and direct experience in Motorsport engineering to base my advice on, yours is more like ritual magic frankly. Put your special pointy hat on and go fool someone more gullible matey.