Notices
 
 

  

User Tag List

Thread: 53 plate Touran battery drain fixed - it was the alarm horn

Results 1 to 3 of 3
  1. 53 plate Touran battery drain fixed - it was the alarm horn 
    #1
    Join Date
    Apr 2014
    Location
    SW London / Surrey
    Posts
    976
    Post Thanks / Like
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    140 Post(s)
    Quick note on a recently solved problem on old Touran in case it helps others. For those wondering it it might explain their similar problem then this is the same platform as a Golf 5, and similar age Audi A3, Seats, etc but I think the general wiring design in the relevant area will be common across other vehicles too.

    For a long time it had been prone to discharging the battery if left for a few days. It's survived through a regime of frequent drives, disconnected battery, and / or battery charger connected.

    I finally found time to systematically track down the cause. This turned out to be an alarm horn with damaged circuit board, which was keeping the "convenience central control unit" (aka J393) active via the LIN bus so that it was drawing ~100mA continuously when the car should have shut everything down after locking.

    The Touran alarm horn is under / behind the (UK) driver side wiper motor - right near the wing. Unfortunately that is where the sunroof drains emerge and presumably has got a bit too wet in the past due to debris blocking the drain to wheel arch. After removing the full-width metal panel at the back of the engine bay the cable on the horn can be unplugged, which allowed the CCC to shut down a minute or so after the car is locked up. The horn itself can be removed on its bracket by undoing the two fairly obvious 10mm nuts that are reachable with suitable socket extensions. I've yet to see if a replacement can be fitted without removing the wiper motor to give better access.

    Discovery of this was by firstly taking the car for a run to charge the battery, disconnecting the +ve terminal to isolate it and putting a multimeter across it (leads with croc clips help) to see where the voltage settled (and wasn't self discharging). Then pulled all SA and SB fuses (the ones on the box next to battery) and reconnected +ve to make sure discharge remained low (ie loss was via a fused circuit). Then steadily replace a few fuses every ~8-12h with multimeter readings every 2-3h to see when a graph of voltage against time hit a steeper fall. This greatly benefitted from having a wiring diagram of the fuses so I could hazard a guess at what to replace next. Result of that was that the SA engine fuse supplying a set of "always on" (terminal 30a) SC cabin fuses was implicated. So using the wiring diagram I was able to repeat the exercise on those fuses. Once the culprit was found multimeter was switched to 200mA mode with leads using 1/4" blade crimps to insert in place of fuse. And that always read ~100mA no matter how long the car had been locked up.

    Matching fuse to circuit diagrams said it was the CCC unit drawing current. That runs off to things like rear door controllers, boot release, sunroof and alarm. It seemed easier to remove some of those at the "destination" end rather than dig the CCC out from behind the glovebox. But dropping head liner trims, etc to achieve that was probably more effort in the end - largely because it didn't kill the drain and so I ended up removing glove box and CCC anyway. In the end I was surprised to find that it wasn't directly removing a power carrying loom that stopped the drain. It was a single skinny black and yellow wire in a 6-pin connector that did. More inspection of wiring diagrams revealed that was the LIN bus wire, and since the car has no interior or inclination alarm sensors the only other thing on it was the alarm horn. As per above, pulling the other end of that in the engine bay fixed the drain problem.

    Looking back a much shorter path to a fix would have been to spot multiple other stories of alarm horns causing battery drain, but they were perhaps more hidden when I didn't have "alarm" in my searches. I think the established theory is that it is a constant attempt to charge the NiMh battery on the horn that causes the drain, but I'm not sure of that after my journey.

    Probably far more info than anyone needs, but if it helps you that's great.
    ======

    Did this forum help you today? Help make sure it's here next time as well. Just click here to make a suitable donation using PayPal .
     
    1 2 0
     

  2. Re: 53 plate Touran battery drain fixed - it was the alarm horn 
    #2
    Join Date
    Apr 2014
    Location
    SW London / Surrey
    Posts
    976
    Post Thanks / Like
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    140 Post(s)
    I can't recall exactly when the battery problems started, but looking back at VCDS scans I see something from about the right time. This "Sounder No Answer" note appeared, but is not treated as a fault:

    Address 46: Central Conv. Labels: 1K0-959-433-MIN.clb
    Part No: 1K0 959 433 C
    ...
    Subsystem 1 - Component: Sounder No Answer

    No fault code found.
    Previously it was:

    Subsystem 1 - Part No: 1K0 951 605 A
    Component: LIN BACKUP HORN H01 1201
    If I'd have spotted that I may well have replaced the alarm horn sooner.
    ======

    Did this forum help you today? Help make sure it's here next time as well. Just click here to make a suitable donation using PayPal .
     
    0 0 0
     

  3. Re: 53 plate Touran battery drain fixed - it was the alarm horn 
    #3
    Join Date
    Jan 2007
    Location
    Nottingham, England
    Posts
    39,550
    Post Thanks / Like
    Blog Entries
    4
    Mentioned
    80 Post(s)
    Tagged
    1 Thread(s)
    Quoted
    1388 Post(s)
    I have known a number of cases on the Golf 5 platform where the siren has failed and triggers the alarm but without sound so draining the battery, you can stop this in VCDS by just coding out the siren if you aren't bothered by not having one. A couple of new sirens we have fitted failed within warranty and it was a paing getting VW to change it, once they insisted the alarm siren fault was down to an ignition switch code so I had to replace the switch and then throw it back at them and they went, "ohh, it's the siren, we will replace it" FFS! Thankfully it isn't common we have to use it but the TPS warranty procedure isn't fit for purpose.
    Slava Ukraini!

     
    0 1 0
     

Similar Threads

  1. Question Touran intermittant battery drain and radiator fan running
    By aidandub8 in forum Touran - Sharan - Caravelle
    Replies: 16
    Last Post: 22-06-2021, 11:29 PM
  2. Please Help Rapid Battery Drain British VW GOLF 2.0l GT FSI 55 Plate 2006 MKV MK5 - Help!
    By MuddyFunkster in forum Golf MK5 - 2004 - 2009
    Replies: 5
    Last Post: 16-07-2011, 01:05 PM
  3. Touran battery drain
    By julesprice in forum Touran - Sharan - Caravelle
    Replies: 7
    Last Post: 24-08-2009, 09:33 PM
  4. Golf GT TDI Mark 5 54 PLate - Battery Drain!?!?!
    By thaidai in forum Archive posts
    Replies: 0
    Last Post: 17-01-2008, 01:08 PM
  5. alarm battery/horn
    By paddymm in forum Audi A4 - Archive Topics
    Replies: 12
    Last Post: 04-04-2007, 09:57 PM
Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


 



  


Disclaimer: VW Audi Forum is an "independant enthusiast website", administered in line with guidelines supplied by VAG in the UK, and is in no way related to any of the Worldwide Volkswagen,Audi,Seat,Skoda,Bentley,Bugatti,Porsche or Lamborghini group of Companies. For official up to date information on any of there vehicles, please visit the official websites. Any comments made throughout this website, are the views of the respective poster, and in no way represent the views of the VW Audi Forum Administration, or the worldwide Volkswagen & Audi Group of companies.


VW Audi Forum do not vet and are not responsible for any information which is posted in this forum. All content is viewed and used by you at your own risk and we do not warrant the accuracy or reliability of any of the information.


Copyright: Certain "words", "phrases" and "Images" used on this website by the Administration are "Copyright" of Volkswagen GB, Volkswagen AG (Germany), Audi GB, Audi AG (Germany), Volkswagen Motorsport GB, Volkswagen Motorsport AG (Germany), Audi Motorsport AG (Germany), Volkswagen Racing GB, Bentley, Bugatti, Porsche and Lamborghini. No image can be replicated by anyone WITHOUT the relevant Companies written permission.


All trademarks and copyrights remain property of their respective owners.

No part of the VW Audi Forum website or forum may be reproduced without written permission from the site administration


PLEASE NOTE - PERSONAL ABUSE, ABUSE AGAINST THIS OR ANY OTHER WEBSITE OR ANY COMPANY WILL NOT BE TOLERATED. OFFENDERS WILL BE MODERATED OR EVEN BANNED.


This website and forum are best viewed at a minimum resolution of 1024 by 768.



  



- VW AUDI Forum - The #1 Volkswagen (VW) Group Forum - Volkswagen (VW) - Audi - Seat - Skoda - Bentley - Bugatti - Lamborghini - Porsche - Scania - MAN - Ducatti - VW Audi Forum -


- www.vwaudiforum.co.uk - www.vwaudiforum.co.uk -