key Battery

[Jim Haseltine]

I suspect that the battery in my key fob is on it's way out - main symptom is that the car often (more often than not) won't unlock keyless and when I use the fob the led often flashes more than once. Other day I got a message flash (and it was a flash - gone before I had a chance to read it all) about the key when I started the car.
I've no handbook so my question is do I need to do anything special when changing the fob battery or is it just a simple old battery out and new one in?

[IanH755]

Battery swap is simple and can be found on the YouTube here - https://www.youtube.com/watch?v=nQulfdQl3_U - then there's a battery "recode" you *might* have to do which I posted a YouTube clip of here - viewtopic.php?f=47&t=119939&p=792052&hi ... ed#p792052

[Jim Haseltine]

Thanks Ian, I'll take a look tonight then change the key battery at the weekend

[grahamh84]

Audi charge me £4 to change the battery


Sent from my iPhone using Tapatalk Pro

[IanH755]

Depending on how quick you are with the actual battery swap you might not have to do the Recode as the fob memory will stay "alive" for around 10 seconds without a battery fitted. Longer than that and it'll need one but give it a check before you start any recoding as it may still work after the swap.

[Jim Haseltine]

Have been seriously busy over the last couple of weeks all I'd done was to buy some batteries but on Saturday I got a warning to change the key battery every time I started the car. Made certain my spare key was working then popped the cover off my usual key and swapped the battery. I suspect it took me about 30 secs to a minute to get the key back together because I had to find something to lever the old battery out but once assembled it worked fine with no coding needed. It might be my imagination, but keyless unlock seems more rapid than previously.
Hasn't made any difference to the bloody tailgate release though, still only opens first time maybe one attempt in three.
One step forwards, one step backwards; the 3rd brake light (which was missing a couple of LEDs) packed in completely this morning.

[douglas96]

Hi Jim.

Regarding your high level brake light fault, this quite possibly could be an easy fix, if you were good with a multimeter and a soldering iron.

I say this as I have taken notes on the high level brake light PCB on my 2005 Superb 3U, however since I haven't worked on a C6 RS6 (yet!) I am unsure of the construction of it on the RS6. I would imagine the same general design would follow through on on both cars.

On my Superb 3U, the high level brake light consists of 16 “7676” type through-hole LEDs. The LEDs measure 7.6mm x 7.6mm (hence why they are called "7676" type) and are of clear construction, however they emit red light. The LEDs are numbered on the PCB as such; D1/1, D1/2, D1/3, D1/4, D2/1, D2/2, etc (see picture) up until D4/4. D4/4 in this case means the 4th array and 4th LED in this array. The LEDs are built in 4 arrays of 4 LEDs each. This means that there are 4 LEDs in series in each of the 4 parallel arrays.

In this case, if one LED fails, then the whole array will not light up. I.e. if D1/3 fails then D1/1, D1/2, D1/3 and D1/4 will not light as these are all required to work in order to complete the circuit. Each array also has a current limiting resistor, in my case the value of this is 34 ohms, signified by the colours of the rings on the resistor. There is also in my case a diode named "D1", connecting the +12V from the plug to the +12V rail on the PCB which supplies each array with power. It is possible that this diode could have failed in your case.

One other thing to check is the pins on the PCB that connect to the plug can come loose and obviously if this has happened could explain why your whole unit has failed.

Once again, I stress that what I have said here is specific to my car, a 2005 Skoda Superb 3U, however I imagine that the general design will most likely be similar in the C6 RS6.

Hopefully this helps!

[Jim Haseltine]

Thanks, that had sort of been my plan - considering the awkwardness of getting to the thing I sourced a new unit yesterday with the intention of taking a look at repairing the old one at my leisure.
Considering that for the last couple of years my leisure time < very little, the old one will probably sit in a box for a decade and then get chucked away....

[douglas96]

Ahh right, as long as you've got it sorted then!

Hahaha, yeah I'm much the same, I keep saying I'll get round to fixing something that inevitably never happens and ends up getting thrown out!

[Jim Haseltine]

One other thing to check is the pins on the PCB that connect to the plug can come loose and obviously if this has happened could explain why your whole unit has failed.

Turns out one of the pins had corroded and snapped off at the base of the socket. Getting the remains of the pin out of the plug wasn't easy, even with the terminal released from the plug body.
Where changing the light unit was concerned, what a pig of a job. Took me best part of an hour to release the lower trim from the tailgate and as for getting the old light unit out - well, let's just say that I exhausted the entire vocabulary of swear words that I've collected in nearly 60 years (in two languages too).

[douglas96]

That's a good find! It's a good job you sourced another unit as you wouldn't want to have to disassemble the tailgate again by the sounds of it! I know exactly the kind of job you mean!

Look on the bright side though, at least you can easily clean your rear window on the Avant after working around it though - it's a bi*** to clean on saloons