2007 328xi Temporary Total Electrical Power Loss

w_alloy · 05-27-2018, 03:56 PM

I have an e90 2007 328xi that has been losing power in a similar manner to those who suffer from the B+ cable connector recall issue. At first I had a complete loss of all power momentarily while driving every few months, where the engine, dashboard, lights, and everything else will shut off for less than a second and then come back online. The frequency and duration of total power loss increased over time, culminating in a 45 minute long loss of power while I was driving it the last time (shutting the hood hard might have brought it back). Outside of these temporary power loss issues there were no other symptoms. However my car was manufactured a few months before the earliest dates that the B+ cable recall covers and the connector was redesigned which created this issue (I have a different connector which afaik has not been known to cause this issue).

I decided to replace the B+ cable connector anyways because I wasn't sure what else the issue could be, in an attempt to avoid heavy repair fees. However now that I have removed the fuse box and disconnected the B+ cable, the cable and connections looked to be in good condition. I've attached some pictures at the bottom of this post.

Are there other issues which could cause these symptoms?

Should I proceed with my original plan of replacing just the end of the cable, replace the whole cable, or replace none of it?

Any other thoughts are appreciated. I'm happy to provide more details. Thanks for your time.

banglenot · 05-27-2018, 06:42 PM

I recently has a intermittent fail on system power on my E60. Systems would glitch suddenly, then stabilize. 30G (sorry, not sure of the name) relay (It's the square black one on the right in your fuse box picture). I replaced mine, $25, stopped the glitches. Unplugs.

That cable looks fine to me.

Here's description of which ECUs are controlled by which sections of the power supply. Newtis has a complete wiring functional diagram that should help you chase it down

https://www.newtis.info/tisv2/a/en/e...supply/2H8WLlz

w_alloy · 05-29-2018, 10:54 PM

Thanks for the tip on the 30g relay! Since it's so cheap I decided to just replace it, reassemble, and see if I keep getting the issue. I drove it for 30 minutes today with no problem.

05-27-2018, 03:56 PM	#1
w_alloy Registered 0 Rep 3 Posts Drives: 2007 328xi Join Date: May 2018 Location: Parts Unkown iTrader: (0)	2007 328xi Temporary Total Electrical Power Loss I have an e90 2007 328xi that has been losing power in a similar manner to those who suffer from the B+ cable connector recall issue. At first I had a complete loss of all power momentarily while driving every few months, where the engine, dashboard, lights, and everything else will shut off for less than a second and then come back online. The frequency and duration of total power loss increased over time, culminating in a 45 minute long loss of power while I was driving it the last time (shutting the hood hard might have brought it back). Outside of these temporary power loss issues there were no other symptoms. However my car was manufactured a few months before the earliest dates that the B+ cable recall covers and the connector was redesigned which created this issue (I have a different connector which afaik has not been known to cause this issue). I decided to replace the B+ cable connector anyways because I wasn't sure what else the issue could be, in an attempt to avoid heavy repair fees. However now that I have removed the fuse box and disconnected the B+ cable, the cable and connections looked to be in good condition. I've attached some pictures at the bottom of this post. Are there other issues which could cause these symptoms? Should I proceed with my original plan of replacing just the end of the cable, replace the whole cable, or replace none of it? Any other thoughts are appreciated. I'm happy to provide more details. Thanks for your time. Last edited by w_alloy; 05-27-2018 at 04:01 PM..
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05-27-2018, 06:42 PM	#2
banglenot Private 38 Rep 85 Posts Drives: 2007 328xiT Join Date: Apr 2018 Location: Ft Lauderdale and Connecticut iTrader: (0)	I recently has a intermittent fail on system power on my E60. Systems would glitch suddenly, then stabilize. 30G (sorry, not sure of the name) relay (It's the square black one on the right in your fuse box picture). I replaced mine, $25, stopped the glitches. Unplugs. That cable looks fine to me. Here's description of which ECUs are controlled by which sections of the power supply. Newtis has a complete wiring functional diagram that should help you chase it down https://www.newtis.info/tisv2/a/en/e...supply/2H8WLlz Last edited by banglenot; 05-27-2018 at 07:06 PM..
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05-29-2018, 10:54 PM	#3
w_alloy Registered 0 Rep 3 Posts Drives: 2007 328xi Join Date: May 2018 Location: Parts Unkown iTrader: (0)	Thanks for the tip on the 30g relay! Since it's so cheap I decided to just replace it, reassemble, and see if I keep getting the issue. I drove it for 30 minutes today with no problem.
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