Greetings All.

I am hoping this forum has tech savvy users that may have witnessed an annoying issue I am having. Diagnostics done with Topdon using guided online diagnostics not just OBD protocols. A1 Sportsback (15k) Left indicator was dead. Audi's comedy response was new headlight. Found supplier of genuine Valeo indicator DRL modules. Bought and fitted. DRL and indicators now works correctly, except vehicle sporadically report the DRL in the NSF is dead. The lights NEVER flicker or stop work. I confirmed this as best I could by filming the lights from the front at 240fps. Not quick in electronic terms but likely fast enough for the low speed CAN bus the lights are on. The lights works fine and the vehicle will drive a mile or so sometimes less then the centre binnacle with show a bulb issue. Sometimes after the report, there are no DTC's, most of the time there is. The DTC changes however. The light module identifies as D6 Light Control Left 2 however this is the headlight control unit on the back of the main body of the lamp. By inspection the DRL/indicator board has no CAN bus of its own as there is no chipset on the board. I have demounted the PCB from the heatsink and note it is a simple single sided aluminium PCB with poor thermal coupling to the HS. Its no wonder these fail. They get very hot and discolour where there is no thermal compound. Whether there is a logged DTC or not, I cam run activation tests and all works. Activate just the DRL leds...fine. Activate just the indicator leds...fine. The codes I see are C11B2F7 and or C123BF6 both flagged as Active/Static but the leds are working. Same brightness as the right side. I also see rarely U112300. This is interesting as it indicates a wider bus issue but from what I have read this code is often generated by a comms issues with the TPMS sensor/s. This is plausible as I had all four tyres replaced last week. The pressures were reregistered with the vehicle straight away.

So the lights work fine but the vehicle says otherwise. Has this been noted by anyone. Don't have time to strip trays, bumper and light out presently without some certainly. Be grateful of any guidance

Schematic shows L177. This is the DRL/indicator module.

 

No one! Is this in the wrong forum? There isn't another coding section is there?

Many Thanks