Thread: Radio causing battery drain? 00858

Hi Guys,

8E B6 A4 Concert 2.

Some of you have been helping out with my parasitic drain issue in the B6 forum(thanks), flagged up some CCM codes and some door lock codes, I found some sheared wires in the door, last place I checked! (AAARRGGHHHH!!), fixed them so no more weird codes when scanning modules, however, the hazard still stays on till I reset a radio code I have....


00858 - Connection; Radio ZF Output to Antenna Amplifier - Short to Ground
36-00 - Open Circuit


When I clear this code it comes back immediately but what I did notice is that even though it comes back, I pull vag cable, lock car and hazard goes off! Result! but the hazard comes back on by my next drive, I can only think its shorting with the cold mornings? Im guessing this means this is definitely causing my drain issue?


What should I do now? Unplug the antenna amp? Anybody else with this issue shed some light?


Thanks

That won't be draining the battery as it is only live when the radio is on

Hmmm, thanks Andy, took radio fuse out and drove home, hazard light on again, did a scan and this time got a code Ive never got, 01134 - Alarm Horn (H12) 29-00 - Short to Ground, cleared and hazard went out. Only thing I can think of now is that theres a damaged wire thats throwing up these inconsistent codes.

Thanks for confirming for me though so I can look elsewhere.

So far-
Alternator is fine
New Battery
CCM fine
Radio not an isse
Door wires fixed
Still the hazard light is on, still battery drain, still frustrating.

Any ideas wouldbe much appreciated

Presumably you've stuck an ammeter on the battery and pulled fuses one by one to see which circuit is the culprit?
I wouldn't trust VAGCOM for this type of fault

Yeah, when I pull fuses, air con and instruments cause it to drop when car unlocked but thats probably because they arent shutting down due to car being open.

When I take a reading and lock the car the drain drops from 0.9 amps to 0.09 amps with hazard on.

When I reset using vagcom the hazard goes out and my readings are much better at 0.9 then after lock drops to 0.05-0.02.

I cant pull fuses while cars locked though.

If it's only when you lock the car, then the first thing I would do is disconnect the alarm as that is one of the few things that goes live when you lock the car. 20-50mA is about the correct current draw if everything is working properly. TBH though 90mA isn't a huge residual draw, would take 600hours to drain a fully charged 60aH battery, obviously a bit less in the real world, but still at least 4 weeks

Thanks Andy, do you know how I can disconnect the alarm? Can you PM me if youd rather not post the info. Basically, I drive home from work, get home, reset hazard, hazard off overnight, hazard still off next morning, unlock car, hazard on, lock car to test, hazard stays on permanently till I reset it again.

Usually with hazard on I have a charge of about 12.6V-12.7V, next morning it would be about 12.2V so a drain of 0.4V overnight.

When Ive reset the the hazard the drain overnight is negligible as when I check the next morning its around 12.55V.

Again, really appreciate the advice. BTW I have tried swapping over with a known working hazard and get the same result.

Voltage readings are pretty irrelevant, you can get a reading of 12v from 8 x AA batteries but doubt they'd be able to start the car! You'll get a voltage drop overnight with any car due to temp. So how long before the drain causes the need to jump start the car?
The alarm is in the boot behind the drivers side light cluster, you have to remove the boot trim to get to it. You can then just unplug the siren. This will log an error, but will at least eliminate the alarm as the culprit.

If I park it Friday evening, by Monday morning it would be dead. Just a click at ignition, central locking wont work etc.

Thanks Ill try that, would the trim need any special clips like the door cards in case I break any?

Is there anything I can do to make sure the alarm is functioning as it should be? Lock car and open each door? Lock car and move around to test motion thingy? any others?

Lock car while still inside, wait 60 seconds then move around and it should go off. The problem with the Audi alarms is they house a backup battery module, these batteries leak after about 6 years and the acid eats away at the PCB and causes problems.
There are metal spring clips around the boot opening, these will tear away from the boot panel, so all you need is a hotmelt glue gun to re-attach them

Yeah it does go off like that when triggered, quick flash of indies and the alarm triggers. Thanks for the heads up re glue gun. Just wondering if its the alarm why Im not getting any codes?

I have read of TT owners instrument panel not shutting down properly and causing drain, fixing by wiring a relay in or replacing instruments.

Does anyone know what the relays under the driver side dash and the fuses under the ECU in the engine bay do? Just wondering if one of these isnt gone and causing a short?

Bit more info, a couple weeks back I pulled fuse 24 (convenience module), hazard went off immediately but Im convinced its not the CCM but rather something in the "loop" like the alarm siren or similar. I will try pull it again and see what it does.

Now when I try clear codes the hazard wont go out at all. Sigh.

Why do you think it isn't the CCM? The B6 is prone to flooding under the carpet due to the ridiculous design of the drain grommets, so it's a common enough problem, even if the carpets don't seem to have been wet.

Carpets are bone dry, the chamber its in is bone dry, the unit itself doesnt look like its seen water and neither does the wiring. VCDS isnt throwing up codes and everything works as it should besides the Hazard light staying on.

From all the cases Ive read of CCM failure there are more symptoms, and they throw up codes.

From what Ive read elsewhere, Audi hazard lights stay on when theres a electrical fault/short/charging problem. Id like to eliminate the cheaper options first and leave CCM till last if possible.

Right, pulled fuse 24 and can confirm it turns the hazard off. Only info I have on systems this controls is as follows.


#24 - Central Convenience Electrical System - Map, Glovebox, Vanity, Trunk and Overhead Lights.


Anybody know if there is anything else it does?


Thanks

Spoke to an auto elec, he said theres probably a split in wiring looms in the doors or one of the door modules is gone, or one of the locks or the CCM is knackered.


He says the CAN system doesnt allow the CCM to power down completely until 20 mins has passed, after that if the system doesnt read as all OK, it stays live.


He said its a PIA and takes time to figure it out. Best bet is to unplug all doors and CCM - drain should drop to about 20-30 milliamps. Strip doors check looms.


Ive already looked at removing the rear door lock and that was a nightmare. How the hell did Audi make so many mistakes with wiring, switches and stupid placement of CCM. Beginning to hate this car

Update, think its got something to do with interior monitoring, when I VCDS I get no codes in interior monitoring or central convenience, I go into measuring blocks in interior monitoring, 01 = 001. Then I turn off ignition while still in measuring blocks, remote lock car 01 quickly shows 000 then back to 001.

Close controller, go into convenience, read codes, code 01616-signal wire to interior monitor, clear that. Hazard off. Drain gone till next drive.

Can't believe how difficult this one is proving to be. Can't offer any useful advice as I know FA about A4.

If the drain goes until the next drive, is it likely to be a relay that is staying active after the car has been used and is not shutting down? If it is a wiring loom issue, how the hell are you going to find it other than identifying the right wires and doing a full traceback? Is there a test that can be done on relays to see if they operate properly?

Yeah its become a real pig of a job. Relays can be tested on a 12v source and meter, but usually when they go you can hear them clicking away. Interesting thing I noticed is when you watch the door leds they do a red flick every second or so for about 30 seconds then they slow down, at the exact time that slowdown occurs the hazard either goes out or doesnt go out.

Im hoping you guys will continue to feed me ideas as its really gone on to long now and I just cant afford to send it to Audi

Another update: Definitely interior monitoring by the looks of it, went outside started car, turned off, hazard on when locking. VCDS plugged in, read codes, no codes, measuring blocks, 01 = 001, lock car and it quickly changes to 000 then back to 001. Turned off Vagcom, locked, LED blinks for a second for about 30 seconds then hazard off as led blinks about once every 4 seconds.

Anyone know whats going on?

Another quick update, unplugged the motion sensor in the light above driver and hazard goes off.


Are there any fuses or relays that this sensor or the interior monitoring/immobiliser etc. are connected through I can check as there are none in the dash on the left of the driver.


Any under the steering wheel or under the ECU as I think I read under the ECU there is a immobiliser fuse?


Thanks for helping everyone!

Only weird thing I can find is that the left and right rear windows measuring block content are different? Windows are operated by crank if that helps..... Any ideas?