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Discussion Starter #61
Battery in and connected read 12.61V
Fired it up... Battery light was still on, than a moment later, "Charging system fault"
Running, I saw 13.8V
Turned every accessory on, 13.7V

Decided I'd disconnect and clean all the ground connections on the battery ground post.
Hear some motor or something running in the headlight area when I removed one of the cables...?! Maybe adaptive headlights....

Fired it back up, and also got a tranny fault which cleared after putting the car in gear...

Went to the car wash, and when leaving, got an OBDII check engine light. I'll go read it...

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Discussion Starter #62
I think at this point, everything is pointing to the connections at the alternator or the alternator itself. That or the LIN line to the central junction box.

She'll be going into the garage for an oil change this week... While they have it in the air, I'll have them check the wiring to the alt.
(And the awful clunking from the front left suspension!)
 

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Typically, these chargers use voltage to determine when the charging should stop. Depending on the charging voltage, when the voltage gets to a predetermined level, and the current drops below a certain value, the charging will stop. As the battery charges, its internal resistance rises, resisting the charge. That internal resistance will make the voltage rise, and the charging current diminish, until cutoff. It is actually the rising internal resistance that causes the current to drop off, and the current draw dropping that causes the voltage to rise. Ray
 

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Checking the connections at the alternator is wise. Rather than a simple "wiggle" test, I suggest that they loosen, and re-tighten the connections, and have them look for corrosion as well. I think the LIN line goes to the alternator, likely through the multi-wire connector. I suggest that they remove and replace this connector several times, in the event of corrosion. Just have them pull it off and reconnect it several times. One other thing I can suggest is to disconnect one of the battery cables and touch it to the other one, holding it for about 30 seconds. This is a hard reset, but it will likely clear any memory issues. You will likely have to reset the stereo presets, and the clock. Since it will also clear the "scratch pad" in the ECM, there may be a few drivability issues until the "scratch pad" updates. Let us know how it goes. Ray
 

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As per schematic that I posted, the LIN line goes directly to the passenger footwell, plugged into the body control module.
I'll suggest the mechanics to clean and reattach alternator ground and power wires.
I've previously did a hard reset... First with a large power resistor between + and - (while disconnected), then directly + and - together for 30 seconds.
No effect... Battery light has never gone off since this issue started.

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I am sorry for coming to this thread so late - dont follow the Evoque forums much. I had the same faults on my 2012 car a couple of years ago (battery light on, charging fault, LIN bus fault or something like that plus fairly good charging voltage) and did a lot of head scratching and testing. I finally spoke to an auto electrical guru who immediately said he has encountered the same snag a few times and the alternator is the problem.

So I removed it and he did an "overhaul" which I think consisted of a new rectifier and bearings. Car has been perfect since.
 

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Discussion Starter #68
Well... Got my oil changed. He didn't do anything with looking at the alternator because he would of had to start taking stuff apart just to get at it....
Ugh!

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I hate to recommend expensive parts without personally checking them, but I suspect the alternator. Possibly a leaking diode causing excessive ripple voltage, the system might condemn the system for that defect. there may be some electronics in the alternator besides the regulator causing the problem. Again, without checking things myself, I hate recommending the replacement of expensive parts. The alternator may be the culprit here. Ray
 

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I'm beginning to think the same, Ray...

I've found a used, low mileage OEM one with 6 month warranty for $100.
I think it'll be worthwhile doing the swap.

Wish I had the time to pull it and just test the diodes... Probably a $5 fix!
 
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