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Thats the thing. The 12v is never gone not even when car is off and doors are locked. Oh wait! you're saying that it should show 12v when car is off and locked but will show 0 when component is on? can you please confirm that?
I reconnected the tv tuner and disconnected the module besides it (radio module?) and voltage became solid. So I'm thinking now it's not the tv tuner but rather the optic ring remains awake and unless I break it by disconnecting any component within that it will stay awake and drain the battery.
I'll do the ring check on vcds and see if it reveals any issues.
Last edited by The.aviator2; 10-26-2017 at 08:34 AM.
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.
You are correct... I always used pin 3 to connect to the white/yellow. It's just the naming of the pin, one should know how to connect.
I still don't get it on how you power up the TV tuner
Originally Posted by 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?
Is this factory installed TV tuner? There is only 1-20 pin connector, how did you power up the TV tuner without all AV1 & AV2? Only 3 power pins are connected? What connector for these 3 pins look like? Where did you get it from? The simplest way to test is to wire these 3 pins to an existing power connector of ANY devices in the Trunk. Follow the instruction on this Video
I went to the car at lunch and checked the sense voltage
Opened the trunk, sense line (Yellow/White) = 11.7V
Turn on the engine and the TV tuner on - sense line = 13.4V while black/red power line = 13.6V Sense line with engine running and TV tuner playing 12V line with engine running Sense line = 11.73V while 12V = 12.05V
Regarding your question, yes the tv tuner is installed from the factory and the 20-pin connector has only three wires. That's red, brown and white/yellow. I also did the optical ring test and it was good. I tested the sense line and got the same results you're getting. However, when you find the time please try to lock the car open the trunk, close the trunk lock (manually) and see if you still have power in the sense line? In my situation, I have constant power in the white/yellow wire whether car is on, off or locked. I'm still not sure if that's normal.
I beleive the white yellow is the diagnostic wire for anything on the most loop.
The radio module on some cars was responsible for a current drain but i think it was earlier than the S8 model line.
As a way to determine which module is drawing power you could bypass each module with a most loop adapter, using it you can unplug the tv tuner for example and bypass the fiber connection so the other modules remain working.
The link below is the adapter I'm referring too.
Also are you sure the lights around the gear-stick go off when you lock the car?
The white yellow is indeed the OSB wakeup line. The problem with measuring the line is the delay involved. It takes a few minutes for the MMI to shut down the devices. Even opening the trunk or a door will wake up the devices. Try looking at the NAV DVD player lights sometime. The second you open the trunk, the player starts up and the lights begin blinking. Try leaving the trunk open for an hour or so and then measure the wakeup line.
Let's get back to beginning of time.
1. Since itā€™s a factory unit, it must be connected BEFORE, all the time and it's been great?
2. When did this battery draining problem start?
3. At current condition, does battery drain with
A. Optical plugged with a loop?
B. Power connector unplugged with optical connector plugged in - no loop?
C. Optical plugged with a loop and power connector unplugged ?
We want to make sure the draining is NOT isolated to just TV tuner. I wasn't sure how you tested the optical from the TV tuner.
If you just unplugged the optical and left it opened, then none of the MMI components are turned on.
Iā€™ll check the power today when I get home.
Cheers,
Louis
Last edited by ltooz_a6_a8_q7; 10-28-2017 at 09:29 PM.
100% sure that all lights turn off around that area including gear stick and hazard light. Yesterday at lunch time I messed around with the cd player, disconnected teh power and reconnected everything back again and put the car to sleep. I do lock everything and wait a few minutes and I can see the ammeter reading to know when systems shut off. After car went to sleep, this time it was showing .02A and for a moment I thought it's the CD player then. However when I unlocked and locked the car, waited a few minutes the reading did not drop passed 0.8A.
The optical loop idea is great. I will see if I can find one locally to save some time. Thanks.
The white yellow is indeed the OSB wakeup line. The problem with measuring the line is the delay involved. It takes a few minutes for the MMI to shut down the devices. Even opening the trunk or a door will wake up the devices. Try looking at the NAV DVD player lights sometime. The second you open the trunk, the player starts up and the lights begin blinking. Try leaving the trunk open for an hour or so and then measure the wakeup line.
I'm with you on this. I lock everything including trunk lock and wait until nav DVD player light goes out then get the amps reading. The draw causing all this hassle is 0.8A.
10-26-2017, 08:12 AM
