Originally Posted by PropellerHead

I have read countless threads about this being an issue with the DSP amp specifically cutting out. If it is a software issue, this happens before the IBUS license is applied to the purchase of the IBUS app/interface. Confirm your license with IBUS and be certain that the DSP option is listed as being part of your purchase. It is an additional charge. DSP and non-nav head units are not mutually exclusive. I have had 2 non-nav E53's with DSP.

Understanding what the DSP amp wants to remain powered or needs wired physically in pair with the IBUS application may help to diagnose the issue.

Before the app and the IBUS harness, people would wire up a spare radio from E38's, E39's, E53's, etc. It only needs the three wires, power, gnd, and IBUS comm. This hardware workaround tells the DSP amp that there is a radio in the loop and allows the DSP amp to stay on rather than cut out.

Excepting an incorrect Riesler interface install, remove and reinstall the IBUS app and be sure it launches on startup with the radio. The app will send the signal to the DSP amp along the IBUS that tells it there is a 'DSP' radio in the loop. This command provides the same information as a physical radio above that is looped into the bus.

The key for either the app or adding an old radio is the physical connection to the amp. The new USB harness *may* address this, but I would confirm that the shop correctly installed the Reisler USB plug into the factory harness. Since mine was not AVIN .plug and play', I had to splice 3 of the cables from the Reisler interface into the IBUS while connected to the USB dongle. But without that correct physical connection, the bus will not get a signal from the IBUS amp- provided it's licensed and being sent in the 1st place. I have understood that this is a function of the interface that prevents over-powering (and killing) the DSP amp.