rialobran

Bit of a long shot, but do you have the RHS panel for the compartment in the boot? Think it's part number 1Z9 868 886

Yep, that's right. That's good to have confirmed, I was wondering if that was the case! I'm used to it being in series in older cars/motorbikes, but I suspected that it might not be the case given all the clever ECU/diagnostics stuff in the Octavia.

Fantastic, thanks for that! Yep, it's got AC fitted. I'll have a poke around for that over the next few days. I'll double check the alternator connector itself too, looked seated when I checked it but will pop it off to look for any contact corrosion etc.

Hi all, I've recently bought a (very high mileage) 2011 vRS and am sorting through the issues on it! Loving the car, although I'm now getting down the list to the "weird issues" section 😁 Most have gone fine, but one that's got me stumped is a fault on the alternator/charge system. On startup, the alternator doesn't switch on/start charging. Once it's been revved above ~1.5k it snaps on and works completely fine, but until that point the whole car is running off the battery. I've attached a VCDS plot to show what's happening -- you can see the voltage dip as the starter motor goes, but then the ECU voltage doesn't rise until I tap the throttle to get the alternator working. My suspicion is that the exciter wire that should provide the "bootstrap" current to the stator is broken somewhere. That'd explain the symptoms -- no output on startup, but once the engine is revved stray inductance means the stator gets just enough current to self-excite, then snaps on. Does anyone have a wiring diagram that might show where I can trace this? Any idea if it just runs through the engine bay, or is it back in to the firewall via ECU/dash? For any other troubleshooting: The battery light turns on when I put the ignition in the 1st position (which would normally indicate exciter current?), and then extinguishes once the engine has started. Picture attached. No particularly relevant DTCs, although I'll post another scan when I'm back to my tools after New Years. There's a few "sensor voltage low" ones, but I think they're because the alternator isn't running on startup. Engine is the 2.0 TSI CCZ. Any insights appreciated!