Autel AL319/519 & Mercedes question

[Ign]

Recently tried to pull codes on an '09 Mercedes E350 AWD Sport w an AL319. It just said "error."

The owner then took it to Autozone (I know, I know) and their first reader also said error. They got a second reader which was successful. I don't know what brand or model(s) as this was relayed to me.

AZ did not clear it, so my wife then took my AL519 and it immediately pulled the code (same code AZ reported).

So, is this an issue specific to a 319 vs 519, or is it just a matter of updates? Both Autels purchased in the last 6 months from Amazon.

 

[Deej]

The other day I was working on a Mercedes, and wasn't really paying too much attention, but couldn't get it to communicate. I only had the key turned one position. Some of the warning lights on the dash came on, so I was assuming I had turned the key to the on position. Once I realized that, I didn't have any problems. I was using an autel