Breezy_Pete

Pin 1 is earth, so just measure from it to each other contact, 2, 3 and 4. Should be no connection.

Don't forget to check for short (0 Ohm) problems between each sensor connector pin and earth.

Yes to all of that I think, including the bit about ignition on, you wouldn't get the engine running with that connector unplugged from ECU. You may find that you need a fine piece of wire to poke into the ECU loom connector to be able to contact your meter probe. I think the pins in the ECU male part are very thin so you won't be able to get contact in the female loom connector without such a 'probe'. (unless you go can go in from the wire entry side?) Can't remember if that's possible/easy.

there is now:

Flat metal box, on the firewall behind airbox.

Wires from the sensor plug are as follows: Pin 1 Brown wire, earth, test for 0 Ohms to battery negative. Pin 2 Green wire, Intake Air Temperature sender to engine ECU pin 56 (on the smaller of the two connectors) Pin 3 Red/green wire, +5V supply from engine ECU pin 62 Pin 4 Brown/white wire, pressure sensor output to engine ECU pin 70 Continuity test those if you can, then test for shorts between pin 1 and each of the others.

Please supply engine code (BBM or BZG?) or VIN. There are two different 2008 1.2 petrol mk2 engines, one with 6 valves the other with 12. Finding the right wiring info probably depends on which you have.

I'm remembering vaguely that the fuel gauge and outside temperature sensor behind the front bumper share a voltage source. Anything odd going on with outside temperature readings? I drew out the circuit within the cluster board somewhere, might be able to find again.

Yes, so your alternator is conventional, fixed output voltage (although that does vary with temperature). Let us know in a few years how it's doing. 👍

The brown/white earth from the gauge should end up on pin 32 of that same connector, check if it does (and that pin connection, can't see well cos of the green peg.

The battery management module would be on the negative pole, not positive, if you had one.

Nice one. Wondered how you got on. 👍

The main relay is on the bottom row of the relay holder in the cabin, in the middle; position #13. Not sure how easy it is to access. That is the 14-way connector, yes.

OK, I don't understand that all. That would imply that either your main relay is switched on all the time* (which seems wrong). Or the wires you're talking about aren't the ones I've tried to describe. * Could be that it gets switched on by door opening, and switches off again when the car goes to sleep after closing/locking??

I hear what you're saying; but I believe the energy recuperation thing isn't the whole story with why EFB/AGM have variable voltage charging. These batteries have lower internal resistance than conventional ones, so for a given charge voltage, the current flows will be higher into the battery. That's great when the battery isn't full, but not so good when it is.

Interesting. I thought EFBs were like AGMs, in that overcharging is a possibility on fixed-voltage output alternators, hence the 'birth' of battery management modules and variable output alternators that go with start/stop cars. You don't have any module connected to the battery negative post do you, just wires?

How odd. I must be misunderstanding how that relay works. What about if key is right out of the ignition? erWin Skoda for circuits. Individual vehicle information tab, repair info, choose model etc. 1 hour's access is under a tenner and you could download huge numbers of pdfs in that time. Download links don't appear until 'flat rate' is paid.

Trouble is, now you don't really have the right battery for your charging system.

Does the car have start/stop? If not there will be nothing to program.

Same thing happened to this guy recently Fabia 1.4 16V BXW Removing intake manifold - Skoda Fabia Mk II (2007-2014) - BRISKODA Function of these sorts of things is generally warm things up to prevent freezing of water content in gas flows. Maybe to stop the point where the block breather output enters the manifold from blocking with ice? I think maybe your airbox has no thermostatic mechanism or source of pre-warmed air to help with this? Earlier generations of 1.4/16V (and other petrol engines) did have (minimum) air temperature control, which often fails in a way that results in all of the air intake being pre-warmed, which ain't ideal.

Fuse 28 (10A) one is on pin 6 of that same 14-way connector blue/black wire one side, black/white on other side of connector pair. Fuse 32 (15A) via pin 3 on blue/red wires.

There are a bunch of other higher-fused feeds that come from the 'main relay' via fuses 28-33 inclusive, which might be safer bets, not strictly ignition switched, but effectively so, they'll be on whenever engine is running.

Black/yellow wires going in and out of the 14-way connector pair near the nearside suspension tower, pin 11, is one option. What do you aim to power from it? That wire is fused at 7.5A (cabin fuse 3), but that fuse serves several different consumers so you wouldn't want to add much load to it.

Engine code please.

If you want to check that PN, message me your VIN.