Daz0925

Hi Guys

I have just changed the sidelight bulbs and filament DRL bulbs for LEDs on my A8 D3 2007 '57'. I have to say the results are extreamly good, they look great. When i choose the bulbs to install, i made sure they were the most suitable, CANBUS friendly etc.*

Unfortunatly all 4 bulbs throw error code after swopping them in and out with the old 1s and cutting my hands to pieces in the mean time.*

Is there anything i can do to remove, disable the bulb error codes on the dash. I have the VCDS software, or will the system learn after a while that there are bulbs there and they are workin correctly. Hope there is an answer to this as results were really good.*

Danyl

Some cara just don't like led's full stop. Canbus is fooled by most but not always.
Could just be one faulty led causing the problem though. Trial and error to replace one at a time and checking for error till you find the culprit. Alternatively you can get in line resistor packs that will fool canbus. But at the same time will stop any bulb out warnings so you have to rely on the old fashioned method of actually checking them lol.

Hope this helps
Dan

snapdragon

Firstly, it has nothing whatsoever to do with the CANBUS, that's just used as marketing technobabble by the people who sell these LED luminairs.

You can't disable the bulb check with VCDS.

The way to address it is to increase the resistance by way of resistors in parallel with the bulbs. The more resistance the better, as long as it exceeds the threshold to disable the broken bulb error. 2W should be enough for sidelights, but the DRLs would probably need at least 10W and the resistors would get quite hot and negate the energy saving of the LEDs.

I have read other people have success using capacitors. The benefit of these is that they don't get hot and what happens is when the LED is first powered on, the capacitor has a low resistance which tricks the broken bulb warning. The capacitor is then charged and the resistance approaches zero. When the light is switched off, the capacitor discharges into the LEDs. 16v electrolytic would be best with the highest uF rating you can fit in the space, and observe +/- polarity.

jakematic

Or negate the A8 buy burning it down

There are several long threads here on LED bulbs.
General consensus has been don't bother with anything but interior 194's and festoons and license plate lamps.

Brozee

Agreed. Scan the archives, as this would have answered your previous concerns. The few people who stuck with lEDs for outside lights besides the license plate light; have found their LEDs burned up or melted in their housings.

FlyTyinFool

+2 (or 3 or 4, wherever we're at...)

I did occasionally receive errors, but not very often. I liked the look quite a lot over the original bulbs.

However, I removed them from the headlamp housings about a month ago, and went back to standard filament style bulbs. I was getting error messages more frequently. I didn't want to start playing games with resistors, capacitors, and such.

I miss the cool look. But I don't miss the warning dings, beeps, and messages. These cars throw enough error messages as it is. Mine's always dinging for one reason or another, usually low washer fluid. This damn car drinks washer fluid like no other car I've ever known!

Anyway, you have 3 choices. You can either live with the errors, play the resistor/capacitor games, or just leave well enough alone. I suppose there is a 4th option. You could buy the 194 bulbs that have a blueish tint to them. I didn't think of that when I was swapping the lamps out a month ago.


Carry on...

Daz0925

Thanks for your help/suggestions.

I have found someone here in the UK who has experience in this field, and have got LEDs to work in A8 headlamps.

They have made a special loom that plugs into the sidelight bulb but powers the DRL bulb using some coding through VCDS which fools the onboard system as the DRL bulb used a greater wattage than the sidelight.

This can still be controlled through the MMI but the sidelight becomes redundant.

So the LED DRL acts as a DRL in the day, and then dims down slightly when the main xenon lights are turned on, this means that no resistors or capacitiors are used.

This seems like the best option to me.

I will keep you posted and send some pictures when it is all done.

snapdragon

Great, where did you get the loom?
Making one is on my to do list for when it stops raining, but if someone makes one that is easier.

absoluTT A3

Based on what you're saying, if you remove a 5W 194 (T10) bulb and replace it with a 3W LED assembly, that should be sufficient to fool CANBUS into thinking there's a serviceable bulb installed. Have you verified that 2W is the testing threshold?