A6 C6 battery issue.
Discussion
Replaced battery about a year ago and replaced with a 920a VARTA direct replacement of the one already fitted to the car. Car has performed faultlessly until recently when it has started to suffer a flat battery if not used for a while or if used for short journeys. Bettery was completely flat this morning and jump started it then put it on a charger.
Passed a Halfords earlier this evening and they offered to test it for free. Technician came out ans connected up the battery tester and it could not test it as it suggested that there was a large drain on the battery. He then tested via the terminals in the nine bay and the same error codes were present.
Technician had no way of qualifying the diagnosis but suggested a large draw from somewhere or that my battery has an internal fault.
Anyone have any ideas on what to do next? Will running a diagnostic check identify the power drain? Dan I safely remove the battery and get that checked independently or will I need to have it recoded?
Thanks
Passed a Halfords earlier this evening and they offered to test it for free. Technician came out ans connected up the battery tester and it could not test it as it suggested that there was a large drain on the battery. He then tested via the terminals in the nine bay and the same error codes were present.
Technician had no way of qualifying the diagnosis but suggested a large draw from somewhere or that my battery has an internal fault.
Anyone have any ideas on what to do next? Will running a diagnostic check identify the power drain? Dan I safely remove the battery and get that checked independently or will I need to have it recoded?
Thanks
When the replacement battery was fitted, did you have it coded to the car? If not that can cause issues. Requires VCDS or dealer tools.
Cars can take ages to shut down - our S5 draws about 12A with the ignition on alone! If there were a deep draw that didn't reduce after full system shut down you'll probably need to go down the route of removing fuses one by one to establish which circuit is drawing load still.
Alarm modules that are failing are frequent culprits but I'd hazard a guess that if the battery wasn't coded when new it's probably getting confused about the state of charge.
Cars can take ages to shut down - our S5 draws about 12A with the ignition on alone! If there were a deep draw that didn't reduce after full system shut down you'll probably need to go down the route of removing fuses one by one to establish which circuit is drawing load still.
Alarm modules that are failing are frequent culprits but I'd hazard a guess that if the battery wasn't coded when new it's probably getting confused about the state of charge.
Unfortunately, followed suppliers advice as they suggested that it didn't need coding if I kept charge to car from aux source. Car warns about shutting down in 3 mins but obviously that is of no help unless you are in the car with ignition on. Battery has been on charge all night and car starts strongly at the moment. Suggested to Halfords tech that I remove battery from the car and bring it down on its own as he suggested that that way he could actually test the battery and rule out a fault with that. He also recommended have the diagnostics done at a main dealer to see if that throws up anything. Battery is only a year old and the supplier has told me to send it back and then if there is a fault they will send a new one and refund the postage. So going to have it checked first as I really don't want to send it back only to find that there is nothing wrong with it. I understand that they will only check it in the same way that Halfords or the AA would.
It absolutely does need to be coded - if it's a non-genuine battery so doesn't have the BEM codes the OEM has, you can simply vary the serial number field by one digit and it will be enough to force the battery management to re-learn the new battery.
You now need to establish whether your current battery is trashed. If it is, starting with a new replacement is a good starter for 10 (ignoring the risk that after sending it away the manufacturer says it's fine so you've had to pay for another replacement!) but if not I would get the existing one on a good quality battery charger (not a 10 quid special that makes a lot of noise and rams current in harder than the battery can take) and get it back to a full charge.
I can look up the exact procedure at home, but it will be close to what I did on our S5 Sportback last weekend. That involves disconnecting a plug on the -ve terminal, which breaks the continuity to the battery management module. It then requires you to log in with VCDS, find the battery management module (61 from memory) if fitted, or if not module 19 for CAN. Adaptation then has drop down menus for entering new battery data which should all be in upper case, in the right format, with the right number of digits.
To see a video of the coding search for "ross tech battery coding" and you'll find one that explains the different procedures. It doesn't talk about non-OEM but basically if you change the serial number, leaving part number and manufacturer along, that should be adequate. You only need to change 1 digit by 1 value and that'll do it.
This forces the control module to learn the new battery and manage it accordingly. At the moment it thinks you've still got the previous one, and that it's really, really shot
If you were local I'd offer to do it for you, but I'm guessing you're nowhere near Gatwick?!
You now need to establish whether your current battery is trashed. If it is, starting with a new replacement is a good starter for 10 (ignoring the risk that after sending it away the manufacturer says it's fine so you've had to pay for another replacement!) but if not I would get the existing one on a good quality battery charger (not a 10 quid special that makes a lot of noise and rams current in harder than the battery can take) and get it back to a full charge.
I can look up the exact procedure at home, but it will be close to what I did on our S5 Sportback last weekend. That involves disconnecting a plug on the -ve terminal, which breaks the continuity to the battery management module. It then requires you to log in with VCDS, find the battery management module (61 from memory) if fitted, or if not module 19 for CAN. Adaptation then has drop down menus for entering new battery data which should all be in upper case, in the right format, with the right number of digits.
To see a video of the coding search for "ross tech battery coding" and you'll find one that explains the different procedures. It doesn't talk about non-OEM but basically if you change the serial number, leaving part number and manufacturer along, that should be adequate. You only need to change 1 digit by 1 value and that'll do it.
This forces the control module to learn the new battery and manage it accordingly. At the moment it thinks you've still got the previous one, and that it's really, really shot
If you were local I'd offer to do it for you, but I'm guessing you're nowhere near Gatwick?!
Hi, thank you for the great advice. I was reluctant to disconnect the battery without following the suppliers advice but am going to and take it to be checked. If it comes back as ok, having been charged via a CTEK charger, then I am going to get the battery recoded by a friend who has all the relevant kit, and knowhow.
If battery is at fault I am going to forward the readout to the supplier and see if they will be prepared to send me another one based on an independent test, worth a go.
Ironically, car seems much better this week. Also hoping that he may be able to check any drain methodically.
If battery is at fault I am going to forward the readout to the supplier and see if they will be prepared to send me another one based on an independent test, worth a go.
Ironically, car seems much better this week. Also hoping that he may be able to check any drain methodically.
Raven Flyer said:
It might seem a stupid question, but what does the MMI display for battery condition show?
I'm going to guess not much! They're not terribly reliable indicators though and in some bases Audi has removed access to it from the MMI. I added it on our S5 but it basically didn't give you much confidence so took it off again.As an indicator of what the right software will tell you about battery condition, here's our S5 one from just before I swapped the battery (it still started the car despite the quoted 2Ah capacity!) - note also the variation between 'actual' state of charge (SOC) and MMI display value (even though it's deactivated)
Checked the new battery this morning, by coincidence, as my wife had done a decent length journey in the car yesterday which was the 1st since changing it:
On original installation and after programming the battery state in MMI was blanked out, but capacity showed 90% SOC and 100Ah (it's a 110Ah battery) so it's interesting to see it's now saying the capacity is 63Ah. Probably temperature related.
youngsyr said:
As a related example of the all-pervading nature of vehicle diagnostic interfaces, a friend worked for a towbar installer - they had equipment designed to make all the necessary coding changes for modules that needed to be taught that a towbar had been installed. Without that if you just added the wiring the car would usually have a fit!
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