Breezy_Pete

And the contacts of the connector are clean and dry?

Yes, because of that pull-up resistor, if there is such a thing. Is there any oil or other fluid inside the sensor connector?

OK, so your readings all look OK then. The signal (yellow/violet wire) probably has a so-called pull-up resistor inside the ECU, so that when the sensor is not doing anything that wire will be pulled up to 5V, as you observed. Very unlikely to be an ECU fault, I think. Use VCDS or other diagnostic software to view live data from this sensor while engine is running.

If both plugs were disconnected when you saw 5V on the violet/yellow wire, then it is shorted to the grey/yellow wire somewhere along its length. That situation is exactly what the fault code suggests.

They won't be the same, or they wouldn't have identical part numbers apart from the suffix. Don't know what the difference is though. Partslink24 lists only the 8K0805615A for a 2023 Superb, even if I search for 8K0805615 without the 'A'.

Circuit looks like this, where 486 in circle at the bottom is an earth connection in engine prewiring harness and D141 is a 5V connection in same harness. Engine ECU is grey section at top of diagram. No relay involved.

Best is to disconnect ECU connector also, yes. Test each contact at the 3-way connector to each of the others, and also to chassis earth (engine metalwork). If both connectors are unplugged each wire should be unconnected with anything else.

If any two seem to be shorted (when unplugged from the sensor) it could indicate that there is wiring damage somewhere in the loom. Damage where insulation has been affected and conductors are touching each other. This is what the fault code could be telling you.

Check from the sensor connector to see if two of the contacts show as being shorted together.

Look at the horizontal bits of each of the seals that the doors shut onto. Any with little puddles on have leaking ancillary carrier seals on that door. Rears are most common.

Removing injectors isn't difficult, but it is indeed time-consuming to do other, major work on these engines (two variants, single and twin cam exist). Getting a compression test done might be about the cheapest and easiest diagnostic aid, or just drive it and see whether the coolant level in the expansion tank falls. I have my doubts that the oil in plug well is relevant.

175k.

Hi, welcome to Briskoda. My world is good today, thanks, how's yours?

Don't worry about it. Unlikely to cause a problem, I think.

Mk3 Fabia seemed to get a flakier ignition switch than previous models, I'm vaguely remembering. Might be worth searching this subforum for threads where ignition switch features.

The fact that fuse 22 is sometimes a source of 12V, but also sometimes a 0V connection will be unexpected by anyone without access to the circuit diagrams.

Unlikely I think, since it isn't controlled by any control modules directly, so it wouldn't be readily monitored as working/not working. Other than step 2, which I doubt would do anything useful, your strategy seems sound. I can't see that just reinstating the correct wiring will fix it, unless the blowing of fuse 22 was the original fault, and not found at the time of the bodgery.

Check that other fuse first, might save you any such work.

Yep. Wild guess that the relay has malfunctioned, and the subsequent bodgery has caused the observed behaviours and faults. Please also check fuse 31 (7.5 Amp rated), which feeds the coil of the washer relay (amongst other things),

Whereabouts are you based?

See above about the unusual configuration of fuse 22.

A subtlety that has just 'unbaffled' me is that the power source for fuse 22 is the rail B621, which itself can be switched up to 12V or down to 0V, thereby giving the reversability of the pump.

The green/white wire marked B622 on left of previous diagram, can be either floating (not connected to anything), 12V or 0V depending on stalk control position. Its origin is shown in the previous page of the diagram.

Relay located in position 1A, apparently:

I think this is the diagram then, with the rectangular box containing 8 coming from fuse 22. So there's a relay involved. V59 is the washer pump. Guessing the green violet wire is the one that's been replaced by a switched 12V from the G65 loom section.