At 9000 miles my e-tron's brakes started pulsing when first starting in the morning. Pulsing goes away completely after the second or third application of the brakes and any stops the rest of the day are completely smooth. This is a difficult problem because it cannot be replicated when you take it to the dealer unless you leave the car overnight. An since I live 100 miles from my dealer it would require 4 trips (2 going and 2 returning) or 400 miles of travel. I did have the dealer look into the issue at the 10000 check-up and were told the rotors and pads looked fine. No help. It is frustrating to get into your $80,000 car every morning and have the first several brake applications strongly pulsate the car to a stop. Any ideas?

 

Educated Speculation:

Sounds like your ABS is engaging, which may be normal in those circumstances. Are you driving with auto-regen enabled? If so, you may expect it to kick in but it doesn't and then you find yourself braking late, thereby engaging the ABS.

There's an algorithm for enabling/disabling regen, but it's not entirely transparent under what circumstances regen is disabled (legit and necessary on slippery surfaces, for example). It can be disabled based on ambient temperature, perhaps also based on weather conditions (gathered from the wiper sensor and possibly other sources) and also possibly based on the state of charge (i.e. if close to 100% - Teslas did that, I'm not sure if Audi does that too, given the allocated top buffer). It's also possible that, in their German wisdom, they are not just disabling automatic regen but regen altogether. While this does eliminate automatic regen, it also entirely eliminates the electromagnetic component of braking, completely changing the pedal feel and the brake engagement characteristics.

I too have experienced what you're describing, a handful of times. The EM braking was absent, had to brake harder for what would otherwise have been a smooth stop, from normal speed. It always happened in the same spot (the first intersection out of the neighborhood) always on a colder day, with a cold car, freshly charged to 80%. Every time the behavior disappeared shortly thereafter (after one or at most two stops). I suspect it's just a crummy algorithm and lack of visual indication that regen is disabled/diminished. It probably uses the first significant deceleration event to assess conditions and then settles on a setting. It's also quite likely that this happens in a narrow temperature range, just above 0C/32F.

 

Toss it in neutral before using the brakes. This will force the mechanical brakes to work rather than regen. Should allow you to test for brake pulsing at any time in your drive cycle.

Could just be flash rust from sitting overnight in humidity causing the brakes to pulse the first application as it cleans the rotors.

 

This is a well-known and frequently discussed observation, consider a forum search.
The Etrons are programmed for a "rotor wipe" function several times each day, usually when first starting out. What that is - is use of only friction brakes in order to remove deposits. The parking brakes use the disc pads, which leaves deposits on the rotor - hence the pulsing. Simply watching the power meter will reveal when this is happening when you step on the brake.

 

Power meter as in showing no regen while braking or is there any other indication?
Either way, crummy implementation as Audis have had the disk wipe feature for a long time, but none of the old ones exhibit this less-than-ideal behavior.

 

Yes, the first few braking incidents can be a little odd since regen is turned off. For me, I have to be aware i may need to press the pedal a little harder when I first start in the morning. I don't really consider it an issue.

 

I remember first reading about the wipe feature when I got my first-gen Q7. The rotor wipe was supposed to happen under normal driving, not under braking and, if I remember correctly, it was triggered by windshield wiper usage.
What we're all describing here is either a new and poor implementation of that or something different. Either way, it doesn't seem to be too frequent or too dramatic.

 

You're comparing apples and oranges. EVs have an entirely different braking system.

 

This is very true! Even between the etron and Tesla there are major differences. Tesla has the mechanical brake and regen (one pedal) braking completely separate 100% of the time. The etron uses a blended regen/brake system similar to Ioniq and others.

 

As they say in my industry, you build to an interface, not to an implementation.