[Akinari]

Installed an aftermarket head unit into my '07 E93 328i, HiFi system, no Comfort Access/SOS/BT/USB. Used the Metra harness for chime retention which comes pre-wired with the steering wheel control harness. Stock speakers, stock amp, head unit is not wired directly to the battery, no dash cams or any other electronics wired.

Everything works flawlessly, steering wheel controls work, strangely my factory chimes are still retained even without the chime retention harness (tested when factory radio was pulled prior to installing harness, not sure if pre-LCI or early production E9x had standalone chime modules).

It's been two days since installing it, and every time I leave the car sitting for more than 30 mins, the car goes into this deep sleep and doesn't respond to key fob presses to lock/unlock the doors unless I'm standing right next to the car. When I start the car I get FM radio static blasting through the speakers at a ridiculous volume, with the date and time reset on the head unit, BUT the custom head unit lighting colour and audio settings including Bluetooth are all saved.

My first thought was the battery being depleted from the install which took a few hours with the interior lights turned on, but I never got any battery warnings, and I drive at least an hour every day and it's been three days since. Then I thought it may be a parasitic battery drain, but it doesn't make sense that only the date and time would be reset on the head unit while the other settings remain.

Tried asking all the local audio shops, no one had any idea what was going on. Is this an issue that's related to the vehicle itself, entering some kind of deep sleep mode or not interacting properly with the head unit/harness, rather than an issue with the head unit or wiring itself?

[ctuna]

Looks like the guy that started this thread has pretty
much the same problem.

https://www.e90post.com/forums/showthread.php?t=1584672

Did you use the same Metra Harness he did?

[Akinari]

Originally Posted by ctuna

Looks like the guy that started this thread has pretty
much the same problem.

https://www.e90post.com/forums/showthread.php?t=1584672

Did you use the same Metra Harness he did?

Same Metra harness

[ctuna]

Doesn't sound like a random coincidence.

[ewicky]

Originally Posted by Akinari

Then I thought it may be a parasitic battery drain, but it doesn't make sense that only the date and time would be reset on the head unit while the other settings remain.

Most HU have a nonvolatile memory as well as power-loss sensitive memory.
In your case, volume, radio station, and clock are power-loss sensitive and the other settings are likely stored in NVRAM.

The reason it's losing everything is likely because the car is shutting off the bistable relay, reserving power only for the next restart of the car. Why the car shuts off the relay is either because one of the BMW modules is refusing to go to sleep (likely because of some interaction between your modifications and the existing BMW systems) or because it is detecting parasitic draw and nipping that in the bud.

Does your head unit shut down automatically when you pull the key out? If not, then it hasn't been wired correctly and is likely pulling parasitic current.

[Akinari]

Originally Posted by ewicky

Most HU have a nonvolatile memory as well as power-loss sensitive memory.
In your case, volume, radio station, and clock are power-loss sensitive and the other settings are likely stored in NVRAM.

The reason it's losing everything is likely because the car is shutting off the bistable relay, reserving power only for the next restart of the car. Why the car shuts off the relay is either because one of the BMW modules is refusing to go to sleep (likely because of some interaction between your modifications and the existing BMW systems) or because it is detecting parasitic draw and nipping that in the bud.

Does your head unit shut down automatically when you pull the key out? If not, then it hasn't been wired correctly and is likely pulling parasitic current.

Head unit does shut down correctly when key is pulled out. I've identified that I haven't wired the harness to the fuse box as the instructions state, so once that's done the reset symptoms shouldn't exist anymore.

Also, realized that I have an early production '07 E93, which has a separate chime and I don't actually need the LC-BMRC-01 harness, which another person on here, as well as another friend of mine, are experiencing the same issues with the car not awakening upon key fob unlock. The other member has used the Metra 70-9003 harness which doesn't have the chime (which I don't need) retention and the steering wheel ASWC-1 harness pre-wired (but I have a spare ASWC-1 harness I can splice in).

Will switch to the 70-9003 harness and wire 12v up to the fuse box and report back soon.