Hi, I recently bought a 2012 A7 3.0 tdi. I've noticed when I'm sat stationary with my foot on the brake and gear engaged (auto) after about 30 seconds I get a burning smell through the vents. If you knock the gear stick into neutral the smell gradually fades.

Took it to Audi dealer who decided it was an oileak on the engine. They failed to find any leak and tried telling me it was DPF regeneration.
My issue with this is why does it only happen when gears are engaged??

 

Apologies for digging up an old thread, but my A7 has the exact issue as this.

Any ideas what it was/is?

Thanks

 

I ended up taking the car to a specialist gearbox company who decided that either the mechatronic unit was on its way out or something more sinister.
I rejected the car as I'd just bought it and got a full refund. For info The Audi deership in Warrington were awful and passed the car back to me as serviceable with no issues.