[cdavi060]

This issue just started yesterday morning. The audio will come on when the car is started but then begin to cut in and out randomly and stay off or on for random amounts of time. Very similar to if the amp was losing power. Same result on all inputs (radio, CD, aux, phone call). Bluetooth seems to work fine as my phone pairs and makes calls.

It worked fine at lunch and on my way home but is back to doing it again this morning. After driving for 15 minutes like this, the off increments got longer and then it cut out completely and did not come back.

It has been cooler in the mornings than usual (mind 50s). But by lunch it is in low 80's again. Not sure if this means anything or not. I will see if it is working again today at lunch.

Does anyone have any ideas what this is, what to troubleshoot or have experienced this in the past?


UPDATE: now the door ajar/key ding sounds go in and out when playing.

[Huckleberry969]

I'm having the same symptoms, but mostly when the car is cold. At 50 degrees, it took about 20-30 minutes before I heard more than a few words on the radio.

The head unit just seems to lose power...the screen goes completely blank. It then comes back about 5 seconds later, only to drop off again 5-10 seconds later. All the other devices (ECU, heated seats, instrument panel, etc) work fine when this is happening. The only other oddity I noticed was that the light inside the BMW 'Call Button' above the mirror came on; it went off as the radio came back.

Through all the Googling and E90 thread searches I've done, several folks came up with a few thoughts, most of them are either of the failing battery or software update school. Having a 4Runner that acts a little weird when the battery is failing, I stopped by the local AutoZone and my battery tested decent...at about 11.9 under load. I still have to research a bit more to see how sensitive BMW electronics are at that voltage. I also disconnected the battery cable, thinking the system would reset itself. Wouldn't you know it, it's never the easy fix.

If this keeps up, I 'might' replace the battery (it's the original) and...GULP...take it to the dealer for analysis.

If you learn anything else, let me know...

[cdavi060]

My display stays on and continues to function, just audio goes in and out.

[SaugaSoul92]

when my battery went bad .. 1 day i had no heat .. panel lit up but no fan pushing heat, then the next day the radio wouldnt work, lit up but no sound.. its weird and the car started fine...check the battery

[cdavi060]

now the door ajar/key ding sounds go in and out when playing.

i had my battery tested a few weeks ago and it had 250 more cold cranking amps than the battery was rated for. battery is really old, but seems to work fine.

local shop found no solution and recommended i take it to the dealer

[ctuna]

A battery that old should be replaced.

A code scan with a BMW capable scanner might help you
fine something.
You might try putting a full charge on the battery and see if
it causes the symptoms to go away for a bit.
Also a scan with a BMW capable scanner might show something
but I would guess the shop did that.

There is something called the IBS system in these cars that allows
them to turn stuff off that it deems unnecessary to keep the car
running . Read about it in the first electrical pdf.

electical e90 pdf
http://www.google.com/url?sa=t&rct=j...,d.cGU&cad=rja
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU

[cdavi060]

Just wanted to post the solution:

Dealer found the SAT (Satelite) module to be faulty. Looped it out of the fiber ring and everything is working again.