yelcab2

Hello,

I have a 2010 A3 S Line with a 2L turbo engine. I have tow head scratchers:

1. EPC light is on. No OBD2 codes. The fault message read by a Renn-Tech tool is something about Starter Circuit Shorted to Ground, which makes no sense to me. I clear it, and it comes right back after car is started.
2. There are a number of lights not working, DRL on the left, head light on the right, right back up light, L and R rear turn signal lights. But, all the bulbs are fine, so it is pointing to some kind of wiring issues.

Has anyone seen wiring issues with A3 lights and where are those wiring issues typically found?
Is there a electrical wiring diagram that is accessible ?

Thanks,
M

Kris Hansen

Circuit shorted to ground is probably a +12v wire that's rubbed through on something. I'd also start looking at fuses for your light problems

yelcab2

I did check the fuses and they are fine.

For example, the fuses for the left and right hand side headlights are fine. But, the right side is not lighting up even after a new bulb was put in.
Second example, the right back up light is out but the bulb is fine, The left side is fine, there are no fuses.
Third example, the left and right rear turn signals are both working but the error messages said they are not.

Something strange is going on,

Perhaps I should chase down the Starter Circuit Short to Ground thing. I don't know if it means 12V is shorted (very unlikely) or the start ignition signal is shorted …

amiram

It looks like a ground connection problem somewhere

yelcab2

I need a wiring diagram to start chasing down a hint or two...

yelcab2

problem found and I am not impressed with Audi electronics, or its documentation.

I had to find, beg, buy, borrow a wiring diagram for a 2010 A3. Went to the HID right side wiring diagram. Measured the head light voltage when the light is on and found it to be 1.7V. Well that's odd. Check the working left side and its 11.8V. Found the fuses controlling that bad left side on the wiring diagram to be Fuses 1 and 16. I searched all over creation just to find the fuse arrangement, it should be printed on the back side of the fuse lid, damn it. Measured voltage at fuse 1, seems normal. Measured voltage at fuse 16 to find 300mV drop across the fuse, and that is very odd. Pulled the fuse to find this fuse partially melted, while not totally blown. Replaced that fuse and the head light works as well as all other error messages are gone.

Now if I can understand that the hell Starter Circuit Shorted to Ground means for the EPC error light to be on????