Audi a4 b8 Horn and Oil level sensor problem.

[DeaDFuN]

Hi! I have an Audi a4 b8 2009 2.0 tdi 136 hp cagb motor code.I have two issues.
My car shows oil min everytime, and the horn is not working. With a vas tester i can read the oil level, and it says 67 mm, wich is enough, soo im sure my sensor is working, and the signal comes till the ecu. I think the issue is somwhere between my ecu and my instrument cluster.
The instrument cluster shows me if the hood is open or closed, so i think the problem is not the hood latch sensor
I took out the horns and they work directly connected to an acumlator. I get no volts from the horn wires, actually both wires have ground, on each side.
The only fault i can read from the tester is "error code 00576 - Terminal 15"

[Smac770]

Do you have a scan tool like VCDS so that you can monitor live data values?

First thing would be to connect to address 0x16, steering wheel electronics, and confirm the horn is identifying as active when you press it. Second thing would be to connect to address 0x09, central electrics, and confirm the horn is identified as active when you press it. The J527 steering wheel electronics, detects the horn press, then says as much over the CAN bus to the J519, central electrics, which then activates the relay that passes power to the horns.

12v power to the J413 horn relay is provided by fuse 7 in column 2 (middle column) on the end of the dash with three fuse columns (not sure which side of the car that might be in your country). You should check the fuse. The fuse is on term 30, battery powered, ie always on. The relay itself would be under the dash behind the headlights switch. The upper middle relay in the rearward relay panel with the wire attached. You have a diesel, so you probably have some relays in the forward relay panel there.

You can check the relay pins. One should be 12v always, one should go to the pin 1 on the two horns, one should be ground, and one is the line that the J519 activates. Can't speak to which wire is attached to which socket pin. The J519 wire should be gray/yellow. The 12v supply wire should be white/red.


As for your fault code, you might need to check the term 15 fuse that feeds the J519. That would be fuse 8 in the black column on that same end of the dash, the three fuse column end.

[DeaDFuN]

The fuse 8 in the black column on the driver side was missing. I put a fuse in it and everything is working perfectly, both the horns and the sensor. Thank you soo much for your help. I was trying to fix it more than 2 weeks and that little fuse was the problem. I dont know how could a fuse disappear.

[Smac770]

Very odd. Maybe someone pulled it and put it back in the wrong slot. It's a 5A fuse.