The.aviator2

Greeting fellow D3 owners,

I've been chasing this battery drain for a month or so now. It started after I picked up the car from the garage with a weak battery which they don't know why a 4-month old battery got weak. I thought it would charge up over time but 2 days later it wouldn't start the car. I went and picked up a fresh VARTA battery, installed it and started the car (jump started actually). Eventually, battery was showing 100% and life was good. After that, I left the car parked for 3 days and came back to find battery has 4 volts left. At first I thought it's the common door button getting stuck so I removed the battery to charge it up and re-installed, cleared faults and everything was good again (100% on MMI). I checked it the next day and battery was showing 50% on MMI. Next, I read about coding the battery for the power module to recognize it so I did that but that did not help.

At that time, I decided to go the old-fashioned way. I locked all doors (trunk too), grabbed a multimeter, hooked it up in series to read current. After a minute or so current settled down to .9A and 1.3A. I started pulling fuses and as soon as I pulled the red 10A fuse from the L/H trunk fuse panel, amps dropped to .02A (BINGO!). I looked up that fuse in elsawin and that's for the TV tuner. I read somewhere that MMI reset fixes such problems but it didn't in my case. The question I want to ask is what keeps the TV tuner awake after car is shutdown and locked?

Any suggestion on what to do next would be appreciated. Thanks.

richard-tx

Did the car come with a TV tuner or did someone add the tuner after the fact?

The.aviator2

It came with the car as a standard equipment. I added the harness for AV1 from Kufatec about a year ago and I don't have any fault codes related for that matter.

ltooz_a6_a8_q7

The tv tuner power connector has a sense line as all components in the trunk, this sense line will wake up the unit when the door, trunk is open. It turns off the unit when not in use.
Check it, but I think one of your door or trunk sensor is open.
How can you add AV1 since it uses the same 20 pin connector? The new cable may have this pin missing.
I replaced my battery a few months ago, tv tuner and everything on, never coded the battery...
Cheers,
Louis

richard-tx

I posted an corrected, updated tuner connector pinout diagram a few months ago.

The.aviator2

the AV1 and AV2 were not used so there was no pins in the 20pin connector related to them. I added the AV1 harness based in Kufatec diagram. AV2 remains vacant.

If i have a bad sensor I would imagine a solid fault code would show for an open sensor. I'm able to clear door sensors faults after physically pressing on them a few times. Moreover, the center console and hazard light turn off normally after locking the door.

To further troubleshoot the problem I disconnected the 20pin connector and re-inserted the 10A fuse and the voltage held steady for a day now. Does that indicate something different?

ltooz_a6_a8_q7

Your TV tuner is never TURNED ON without the 20 pins. Now I know Kutafec makes incomplete or bad cables.





Cheers,
Louis

richard-tx

Pin 3 is NOT an open diagnostic lead. It is supposed to be connected to the OBD wakeup/sleep lead. This is the white/yellow wire used for the satellite radio as well as other things like the Nav DVD player.. If you want verification, look the the Elsa-Win schematics for the A8.

The.aviator2

I tested that wakeup sense line (yellow/white) and it's reading 12v all the time. That explains why the tv tuner stays awake. I removed Kufatec harness and problem is still there if I connect the 20-pin connector back on. I traced the sensing wire and it passes through dash panel. If what I'm thinking is right, I'm afraid I read about this problem in another thread in here some time ago.

How could I verify if the sensing line is shorted? Should I try to disconnect it from the data bus J533? That's behind the glove box right?

ltooz_a6_a8_q7

It’s supposed to be 12v, should be gone when the unit is on