Auxiliary Air Conditioning Not Activating

Audi A3 E-tron Forum

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Apr 17, 2024
Sonoma County
I just bought a "new to me" 2018 A3 E-tron and I'm really loving the car. Coming from a VW GTI and E-golf, the A3 feels so much more buttoned down.

One thing I've noticed though, is I'm not able to activate the Auxiliary Air Conditioning through the MMI. When I click on "Turn on auxiliary AC", nothing happens. The menu continues to show "Turn on auxiliary AC" and the status shows Not Active. The HVAC system does not turn on if it was off to begin with and there are no error messages.

I also tried activating the aux ac through by setting the timer then turning the car off. The MMI shows that there is an aux ac timer set, but the time comes and goes with nothing happening. I thought it might work like the e-golf where you have to set the timer around 5 to 10 minutes before the time you want the aux ac to precondition the car so I tried that. No dice.

If I step on the brake pedal, turn on the car to show "ready" and keep the car in EV mode, the AC works perfectly. So I can still enjoy the AC on my lunch break, but I can't schedule preconditioning.

Anyone else run into this and perhaps have some pointers?
Hi there, I have a 2018 too... This feature was working beautifully until one of the recalls messed it up. My car was still under warranty at the time and spent at least a month at the dealer while they attempted all sorts of fixes but never succeeded.. They replaced the entire climate control unit, the display etc... In the end I found a way to make it work: Like you say program the timer.. The first couple of times it didn't work because of the system automatically advancing the date to the next day... It's very hard to notice... So after you program the time to be several minutes later than "now", be sure to check the date and see if it automatically advanced to "tomorrow" and then change it back to "today"... it is a PITA but at least I can get the car to pre-heat in the cold mornings. Just double check the date and it should work.
I ran into the timer's automatic advancing to the next day and you're right, it's stupidly subtle. I initially thought I had fat fingered the dial to the next day. I used OBDeleven and found several random faults in the "air conditioning" section. I cleared them and I was able to get the timer function to start the aux AC. It's still a little quirky though as the timer functionality is intermittent.

Other observations while playing with the aux ac system:
- When I skip setting the timer, and click on "Turn on auxiliary AC", the AC will turn on but the MMI menu option to "Turn off aux ac" does nothing. I can shut it off with the fan button instead. I figured, if I want to jump into the car during lunch break, I can just turn the car on in EV mode to enjoy the HVAC.
- If the car is plugged into a 120V L1 outlet to charge, the aux AC doesn't really provide much cooling or heating. Then again, I only let it run for 5 minutes testing at LO and HI temp settings. I have yet to see how it performs when the car is plugged into a 240V L2 outlet.
The 93M2 recall update broke both the aux AC and the charging timer. The aux AC didn't work at all, manually or by schedule, and the charging timer would intermittently charge immediately when it would be waiting for the preferred charging time. Audi fixed the aux AC by replacing the charging module (I think it took 2 tries). The charging timer was never fixed, but after purchasing an Emporia smart charger I realized that even if it worked perfectly, the Audi charger scheduling software is rather lame in functionality.
the inability to run aux heat or AC at full power with 110V i think is a documented limitation... i have 240 and can see the power draw... not quite the 3.4 kW max on a full battery but i can see over 2 kW peaks... something 110V cannot handle. on 240V the heater can defrost all windows and warm the interior nicely after its 45 min run time even on a freezing cold day. almost 2 kWh of power consumed each time...